diff --git a/website/src/lib/components/Help.svelte b/website/src/lib/components/Help.svelte
index 3e88a29d..19208656 100644
--- a/website/src/lib/components/Help.svelte
+++ b/website/src/lib/components/Help.svelte
@@ -3,6 +3,6 @@
 </script>
 
 <div class="{$$props.class || ''} text-sm rounded border flex flex-row items-center p-2">
-	<CircleHelp size="16" class="w-10 mr-2" />
+	<CircleHelp size="16" class="w-4 mr-2 shrink-0 grow-0" />
 	<slot />
 </div>
diff --git a/website/src/lib/components/layer-control/LayerControlSettings.svelte b/website/src/lib/components/layer-control/LayerControlSettings.svelte
index c9f465c9..d4cb8794 100644
--- a/website/src/lib/components/layer-control/LayerControlSettings.svelte
+++ b/website/src/lib/components/layer-control/LayerControlSettings.svelte
@@ -120,7 +120,7 @@
 						<div class="flex flex-row items-center justify-between gap-4">
 							<Label>{$_('menu.color')}</Label>
 							<Select.Root bind:selected={$selectedHeatmapColor} class="grow">
-								<Select.Trigger class="w-full">
+								<Select.Trigger class="w-full h-8">
 									<Select.Value placeholder="Theme" />
 								</Select.Trigger>
 								<Select.Content>
diff --git a/website/src/lib/components/toolbar/Toolbar.svelte b/website/src/lib/components/toolbar/Toolbar.svelte
index 694f9848..af76aae1 100644
--- a/website/src/lib/components/toolbar/Toolbar.svelte
+++ b/website/src/lib/components/toolbar/Toolbar.svelte
@@ -40,7 +40,7 @@
 			</ToolbarItem>
 			<ToolbarItem tool={Tool.MERGE}>
 				<Group slot="icon" size="18" />
-				<span slot="tooltip">{$_('toolbar.merge_tooltip')}</span>
+				<span slot="tooltip">{$_('toolbar.merge.tooltip')}</span>
 			</ToolbarItem>
 			<ToolbarItem tool={Tool.EXTRACT}>
 				<Ungroup slot="icon" size="18" />
diff --git a/website/src/lib/components/toolbar/ToolbarItemMenu.svelte b/website/src/lib/components/toolbar/ToolbarItemMenu.svelte
index d4ecd687..09ab54d2 100644
--- a/website/src/lib/components/toolbar/ToolbarItemMenu.svelte
+++ b/website/src/lib/components/toolbar/ToolbarItemMenu.svelte
@@ -5,6 +5,7 @@
 	import Routing from '$lib/components/toolbar/tools/routing/Routing.svelte';
 	import Scissors from '$lib/components/toolbar/tools/Scissors.svelte';
 	import Waypoint from '$lib/components/toolbar/tools/Waypoint.svelte';
+	import Merge from '$lib/components/toolbar/tools/Merge.svelte';
 	import RoutingControlPopup from '$lib/components/toolbar/tools/routing/RoutingControlPopup.svelte';
 	import { onMount } from 'svelte';
 	import mapboxgl from 'mapbox-gl';
@@ -36,6 +37,8 @@
 						<Scissors />
 					{:else if $currentTool === Tool.WAYPOINT}
 						<Waypoint />
+					{:else if $currentTool === Tool.MERGE}
+						<Merge />
 					{/if}
 				</Card.Content>
 			</Card.Root>
diff --git a/website/src/lib/components/toolbar/tools/Merge.svelte b/website/src/lib/components/toolbar/tools/Merge.svelte
new file mode 100644
index 00000000..55caa4e7
--- /dev/null
+++ b/website/src/lib/components/toolbar/tools/Merge.svelte
@@ -0,0 +1,100 @@
+<script lang="ts" context="module">
+	enum MergeType {
+		TRACES = 'traces',
+		CONTENTS = 'contents'
+	}
+</script>
+
+<script lang="ts">
+	import { ListFileItem, ListTrackItem } from '$lib/components/file-list/FileList';
+	import Help from '$lib/components/Help.svelte';
+	import { selection } from '$lib/components/file-list/Selection';
+	import { Button } from '$lib/components/ui/button';
+	import { Label } from '$lib/components/ui/label/index.js';
+	import * as RadioGroup from '$lib/components/ui/radio-group';
+	import { _ } from 'svelte-i18n';
+	import { dbUtils, fileObservers } from '$lib/db';
+	import { get } from 'svelte/store';
+
+	let canMergeTraces = false;
+	let canMergeContents = false;
+
+	$: if ($selection.size > 1) {
+		canMergeTraces = true;
+	} else if ($selection.size === 1) {
+		let selected = $selection.getSelected()[0];
+		if (selected instanceof ListFileItem) {
+			let fileId = selected.getFileId();
+			let fileStore = $fileObservers.get(fileId);
+			if (fileStore) {
+				let file = get(fileStore)?.file;
+				if (file) {
+					canMergeTraces = file.getSegments().length > 1;
+				} else {
+					canMergeTraces = false;
+				}
+			} else {
+				canMergeTraces = false;
+			}
+		} else if (selected instanceof ListTrackItem) {
+			let fileId = selected.getFileId();
+			let trackIndex = selected.getTrackIndex();
+			let fileStore = $fileObservers.get(fileId);
+			if (fileStore) {
+				let file = get(fileStore)?.file;
+				if (file) {
+					canMergeTraces = file.trk[trackIndex].getSegments().length > 1;
+				} else {
+					canMergeTraces = false;
+				}
+			} else {
+				canMergeTraces = false;
+			}
+		} else {
+			canMergeContents = false;
+		}
+	}
+
+	$: canMergeContents =
+		$selection.size > 1 &&
+		$selection
+			.getSelected()
+			.some((item) => item instanceof ListFileItem || item instanceof ListTrackItem);
+
+	let mergeType = MergeType.TRACES;
+</script>
+
+<div class="flex flex-col gap-3 max-w-96">
+	<RadioGroup.Root bind:value={mergeType}>
+		<div class="flex flex-row items-center gap-2">
+			<RadioGroup.Item value={MergeType.TRACES} id={MergeType.TRACES} />
+			<Label for={MergeType.TRACES}>{$_('toolbar.merge.merge_traces')}</Label>
+		</div>
+		<div class="flex flex-row items-center gap-2">
+			<RadioGroup.Item value={MergeType.CONTENTS} id={MergeType.CONTENTS} />
+			<Label for={MergeType.CONTENTS}>{$_('toolbar.merge.merge_contents')}</Label>
+		</div>
+	</RadioGroup.Root>
+	<Button
+		variant="outline"
+		disabled={(mergeType === MergeType.TRACES && !canMergeTraces) ||
+			(mergeType === MergeType.CONTENTS && !canMergeContents)}
+		class="w-full"
+		on:click={() => {
+			dbUtils.mergeSelection(mergeType === MergeType.TRACES);
+		}}
+	>
+		{$_('toolbar.merge.merge_selection')}
+	</Button>
+	<Help>
+		{#if mergeType === MergeType.TRACES && canMergeTraces}
+			{$_('toolbar.merge.help_merge_traces')}
+		{:else if mergeType === MergeType.TRACES && !canMergeTraces}
+			{$_('toolbar.merge.help_cannot_merge_traces')}
+		{:else if mergeType === MergeType.CONTENTS && canMergeContents}
+			{$_('toolbar.merge.help_merge_contents')}
+		{:else if mergeType === MergeType.CONTENTS && !canMergeContents}
+			{$_('toolbar.merge.help_cannot_merge_contents')}
+		{/if}
+	</Help>
+</div>
diff --git a/website/src/lib/db.ts b/website/src/lib/db.ts
index 379d9b9a..a95ea5f6 100644
--- a/website/src/lib/db.ts
+++ b/website/src/lib/db.ts
@@ -1,5 +1,5 @@
 import Dexie, { liveQuery } from 'dexie';
-import { GPXFile, GPXStatistics, Track, type AnyGPXTreeElement } from 'gpx';
+import { GPXFile, GPXStatistics, Track, type AnyGPXTreeElement, TrackSegment, Waypoint, TrackPoint } from 'gpx';
 import { enableMapSet, enablePatches, applyPatches, type Patch, type WritableDraft, castDraft, freeze, produceWithPatches, original, produce } from 'immer';
 import { writable, get, derived, type Readable, type Writable } from 'svelte/store';
 import { initTargetMapBounds, updateTargetMapBounds } from './stores';
@@ -187,31 +187,31 @@ function dexieGPXFileStore(id: string): Readable<GPXFileWithStatistics> & { dest
     };
 }
 
-// Add/update the files to the database
-function updateDbFiles(files: (GPXFile | undefined)[]) {
-    let filteredFiles = files.filter(file => file !== undefined) as GPXFile[];
-    let fileIds = filteredFiles.map(file => file._data.id);
-    return db.transaction('rw', db.fileids, db.files, async () => {
-        await db.fileids.bulkPut(fileIds, fileIds);
-        await db.files.bulkPut(filteredFiles, fileIds);
-    });
-}
-
-// Delete the files with the given ids from the database
-function deleteDbFiles(fileIds: string[]) {
-    return db.transaction('rw', db.fileids, db.files, async () => {
-        await db.fileids.bulkDelete(fileIds);
-        await db.files.bulkDelete(fileIds);
-    });
-}
-
 // Commit the changes to the file state to the database
 function commitFileStateChange(newFileState: ReadonlyMap<string, GPXFile>, patch: Patch[]) {
-    if (newFileState.size >= fileState.size) {
-        return updateDbFiles(getChangedFileIds(patch).map((fileId) => newFileState.get(fileId)));
-    } else {
-        return deleteDbFiles(getChangedFileIds(patch));
-    }
+    let changedFileIds = getChangedFileIds(patch);
+    let updatedFileIds: string[] = [], deletedFileIds: string[] = [];
+    changedFileIds.forEach(id => {
+        if (newFileState.has(id)) {
+            updatedFileIds.push(id);
+        } else {
+            deletedFileIds.push(id);
+        }
+    });
+
+    let updatedFiles = updatedFileIds.map(id => newFileState.get(id)).filter(file => file !== undefined) as GPXFile[];
+    updatedFileIds = updatedFiles.map(file => file._data.id);
+
+    return db.transaction('rw', db.fileids, db.files, async () => {
+        if (updatedFileIds.length > 0) {
+            await db.fileids.bulkPut(updatedFileIds, updatedFileIds);
+            await db.files.bulkPut(updatedFiles, updatedFileIds);
+        }
+        if (deletedFileIds.length > 0) {
+            await db.fileids.bulkDelete(deletedFileIds);
+            await db.files.bulkDelete(deletedFileIds);
+        }
+    });
 }
 
 export const fileObservers: Writable<Map<string, Readable<GPXFileWithStatistics | undefined> & { destroy: () => void }>> = writable(new Map());
@@ -487,6 +487,118 @@ export const dbUtils = {
             });
         });
     },
+    mergeSelection: (mergeTraces: boolean) => {
+        applyGlobal((draft) => {
+            let first = true;
+            let target: ListItem = new ListRootItem();
+            let targetFile: GPXFile | undefined = undefined;
+            let toMerge: {
+                trk: Track[],
+                trkseg: TrackSegment[],
+                wpt: Waypoint[]
+            } = {
+                trk: [],
+                trkseg: [],
+                wpt: []
+            };
+            applyToOrderedSelectedItemsFromFile((fileId, level, items) => {
+                let file = original(draft)?.get(fileId);
+                if (file) {
+                    let newFile = file;
+                    if (level === ListLevel.FILE) {
+                        {
+                            let [result, removed] = newFile.replaceTracks(0, newFile.trk.length - 1, []);
+                            toMerge.trk.push(...removed);
+                            newFile = result;
+                        }
+                        {
+                            let [result, removed] = newFile.replaceWaypoints(0, newFile.wpt.length - 1, []);
+                            toMerge.wpt.push(...removed);
+                            newFile = result;
+                        }
+                        if (first) {
+                            target = items[0];
+                            targetFile = newFile;
+                        } else {
+                            draft.delete(fileId);
+                        }
+                    } else {
+                        if (level === ListLevel.TRACK) {
+                            items.forEach((item, index) => {
+                                let trackIndex = (item as ListTrackItem).getTrackIndex();
+                                if (index === items.length - 1) { // Order is reversed, so the last track is the first one and the one to keep
+                                    let [result, removed] = newFile.replaceTrackSegments(trackIndex, 0, newFile.trk[trackIndex].trkseg.length - 1, []);
+                                    toMerge.trkseg.splice(0, 0, ...removed);
+                                    newFile = result;
+                                    target = item;
+                                } else {
+                                    let [result, removed] = newFile.replaceTracks(trackIndex, trackIndex, []);
+                                    toMerge.trkseg.push(...removed[0].trkseg);
+                                    newFile = result;
+                                }
+                            });
+                        } else if (level === ListLevel.SEGMENT) {
+                            items.forEach((item, index) => {
+                                let trackIndex = (item as ListTrackSegmentItem).getTrackIndex();
+                                let segmentIndex = (item as ListTrackSegmentItem).getSegmentIndex();
+                                if (index === items.length - 1) { // Order is reversed, so the last segment is the first one and the one to keep
+                                    target = item;
+                                }
+                                let [result, removed] = newFile.replaceTrackSegments(trackIndex, segmentIndex, segmentIndex, []);
+                                toMerge.trkseg.splice(0, 0, ...removed);
+                                newFile = result;
+                            });
+                        }
+                        if (first) {
+                            targetFile = newFile;
+                        } else {
+                            draft.set(fileId, freeze(newFile));
+                        }
+                    }
+                    first = false;
+                }
+            });
+
+            if (mergeTraces) {
+                if (toMerge.trk.length > 0) {
+                    let trackPoints: TrackPoint[] = [];
+                    toMerge.trk.forEach((track) => {
+                        track.trkseg.forEach((segment) => {
+                            trackPoints = trackPoints.concat(segment.trkpt.slice());
+                        });
+                    });
+                    // TODO adapt timestamps of trackPoints
+                    toMerge.trk[0] = toMerge.trk[0].replaceTrackPoints(0, 0, toMerge.trk[0].trkseg[0].trkpt.length - 1, trackPoints);
+                    toMerge.trk[0] = toMerge.trk[0].replaceTrackSegments(1, toMerge.trk[0].trkseg.length - 1, [])[0];
+                    toMerge.trk = toMerge.trk.slice(0, 1);
+                }
+                if (toMerge.trkseg.length > 0) {
+                    let trackPoints: TrackPoint[] = [];
+                    toMerge.trkseg.forEach((segment) => {
+                        trackPoints = trackPoints.concat(segment.trkpt.slice());
+                    });
+                    // TODO adapt timestamps of trackPoints
+                    toMerge.trkseg[0] = toMerge.trkseg[0].replaceTrackPoints(0, toMerge.trkseg[0].trkpt.length - 1, trackPoints);
+                    toMerge.trkseg = toMerge.trkseg.slice(0, 1);
+                }
+            }
+
+            if (targetFile) {
+                if (target instanceof ListFileItem) {
+                    targetFile = targetFile.replaceTracks(0, targetFile.trk.length - 1, toMerge.trk)[0];
+                    targetFile = targetFile.replaceWaypoints(0, targetFile.wpt.length - 1, toMerge.wpt)[0];
+                } else if (target instanceof ListTrackItem) {
+                    let trackIndex = target.getTrackIndex();
+                    targetFile = targetFile.replaceTrackSegments(trackIndex, 0, -1, toMerge.trkseg)[0];
+                } else if (target instanceof ListTrackSegmentItem) {
+                    let trackIndex = target.getTrackIndex();
+                    let segmentIndex = target.getSegmentIndex();
+                    targetFile = targetFile.replaceTrackSegments(trackIndex, segmentIndex, segmentIndex - 1, toMerge.trkseg)[0];
+                }
+                draft.set(targetFile._data.id, freeze(targetFile));
+            }
+        });
+    },
     deleteSelection: () => {
         if (get(selection).size === 0) {
             return;
diff --git a/website/src/locales/en.json b/website/src/locales/en.json
index 0e24c0c5..0dbe2195 100644
--- a/website/src/locales/en.json
+++ b/website/src/locales/en.json
@@ -105,7 +105,16 @@
             "tooltip": "Trim or split routes"
         },
         "time_tooltip": "Manage time and speed data",
-        "merge_tooltip": "Merge file elements together",
+        "merge": {
+            "merge_traces": "Connect the traces",
+            "merge_contents": "Merge the contents and keep the traces disconnected",
+            "merge_selection": "Merge selection",
+            "tooltip": "Merge file elements together",
+            "help_merge_traces": "Connecting the selected traces will result in a single file containing a single continuous trace",
+            "help_cannot_merge_traces": "Your selection needs to contain several traces to connect them",
+            "help_merge_contents": "Merging the contents of the selected file elements will group all the contents inside the first file element",
+            "help_cannot_merge_contents": "Your selection needs to contain several file elements to merge their contents"
+        },
         "extract_tooltip": "Extract inner tracks or segments",
         "waypoint_tooltip": "Create and edit points of interest",
         "reduce_tooltip": "Reduce the number of GPS points",