Keyboard & Mouse Shortcuts¶

The most important shortcuts are always shown in the status bar at the bottom of the screen. These shortcut hints depend on the active tool and also change when modifiers are pressed to allow easy exploration of available functionality.

A complete listing of all available keyboard & mouse shortcuts for WEBKNOSSOS can be found below. All shortcuts shown here are the default bindings. Keyboard-only shortcuts can be customized per user account (see Customizing Shortcuts below).

Customizing Shortcuts¶

All keyboard shortcuts that do not involve mouse buttons can be freely customized per user account. Open the shortcut configuration via the navbar menu → "Keyboard Shortcuts".

From there you can:

View all current keyboard bindings grouped by category.
Edit any shortcut by clicking the pencil icon next to it and recording a new key combination.
Add additional alternative bindings for any action (useful if you want two different keys or key combinations to trigger the same action).
Remove bindings you never use.
Reset individual shortcuts or all shortcuts to their defaults at any time.
Multi-stroke sequences: Shortcuts can consist of more than one consecutive keystroke. For example, a two-stroke binding like Ctrl+K followed by B is recorded just like any other shortcut — press and release the first chord, then the second. The recorder captures the full sequence automatically.

Shortcut changes are saved to your user account and persist across devices and browsers.

Key labels for special symbol keys (+, ], …)

Correctly labeling shortcuts that use punctuation or symbol keys (e.g. +, #, [) requires the browser to know your keyboard layout.

Chrome and Edge expose this information via the Keyboard Layout API and always show the correct character label immediately.

Firefox, Safari, and other browsers do not support this API. WEBKNOSSOS works around this limitation by learning your layout at runtime: The first time you press a symbol key without any modifier (no Shift, Ctrl, etc.), the correct label is detected and stored for your session and future sessions in your browser. Until a key has been pressed at least once this way, it falls back to the US layout label. Regardless of a key being recorded, the shortcut should always be available.

If you switch your operating-system keyboard layout mid-session, the stored labels become stale. Pressing any symbol key unmodified again will clear the old mapping and pick up the new layout automatically.

General¶

Key Binding	Operation
`Ctrl` / `Cmd` + `Z`	Undo
`Ctrl` / `Cmd` + `Y`	Redo
`Ctrl` / `Cmd` + `S`	Save
`I` or `Ctrl` / `Cmd` / `Alt` + Mousewheel	Zoom In
`O` or `Ctrl` / `Cmd` / `Alt` + Mousewheel	Zoom Out
`P`	Select Previous Comment
`N`	Select Next Comment
`3`	Toggle Segmentation Opacity
`H`	Increase the Move Value
`G`	Decrease the Move Value
`Q`	Download Screenshot(s) of Viewport(s)
`.`	Toggle Viewport Maximization
`Shift` + `1`	Switch to Plane (Orthogonal) View Mode
`Shift` + `2`	Switch to Flight View Mode
`K` , `L`	Toggle left/right Sidebars
`Ctrl` / `Cmd` + `P`	Open command palette

Skeleton Annotation Mode¶

Key Binding	Operation
`M`	Toggle Mode (Orthogonal, Flight, Oblique; disabled while proofreading)
`1`	Toggle Visibility of all Trees
`2`	Toggle Visibility of Inactive Trees
`Shift` + Mousewheel	Change Node Radius
`Ctrl` / `Cmd` + `Shift` + `F`	Open Tree Search (if Tree List is visible)
`F` or Mousewheel	Move Forward by a Single Slice
`D` or Mousewheel	Move Backward by a Single Slice

Orthogonal Mode¶

Note that skeleton-specific mouse actions and some keyboard shortcuts are only available when the skeleton tool is active.

Key Binding	Operation
Left Mouse Drag or Arrow Keys	Move In-Plane
`Alt` + Mouse Move	Move In-Plane
`Space`	Move Forward
`Shift` + `Up` / `Down` / `Left` / `Right` `Alt` + `Left` / `Right`	Rotate Planes
`Ctrl` / `Cmd` + `Shift` + `Up` / `Down` / `Left` / `Right` `Ctrl` / `Cmd` + `Alt` + `Left` / `Right`	Rotate Planes by 90°
Right-Click Drag (3D View)	Rotate 3D View
Left Click	Create New Node (Skeleton tool)
Left Click	Select Node (Mark as Active Node) under cursor (Skeleton tool)
Left Drag	Move node under cursor (Skeleton tool)
Right Click (on node)	Bring up the context-menu with further actions (Skeleton tool)
`Shift` + `Alt` + Left Click	Merge Two Nodes and Combine Trees (Skeleton tool)
`Shift` + `Ctrl` / `Cmd` + Left Click	Delete Edge / Split Trees (Skeleton tool)
`C`	Create New Tree (Skeleton tool)
`Ctrl` / `Cmd` + Left Click or `Ctrl` / `Cmd` + Arrow Keys	Move the Active Node (Skeleton tool)
`Del`	Delete Node / Split Trees (Skeleton tool)
`B`	Mark Node as New Branchpoint (Skeleton tool)
`J`	Delete Branch Point (Skeleton tool)

The following keyboard shortcuts are available in plane mode regardless of the active tool:

Key Binding	Operation
`E`	Move along annotation direction
`R`	Move backward along annotation direction
`S`	Center Camera on Active Node
`Ctrl` / `Cmd` + `.`	Navigate to the next Node (Mark as Active)
`Ctrl` / `Cmd` + `,`	Navigate to previous Node (Mark as Active)
`Ctrl` / `Cmd` + `I`	Copy Segment ID under Cursor

Note that you can enable Classic Controls which will behave slightly different and more explicit for the mouse actions:

Key Binding	Operation
Right Click	Create New Node
`Shift` + Left Click	Select Node (Mark as Active Node)

Flight / Oblique Mode¶

Key Binding	Operation
Left Click	Select Node (Mark as Active Node) under cursor
Left Mouse Drag or Arrow Keys	Rotation
`Space`	Move Forward
`Ctrl` / `Cmd` + `Space`	Move Backward
`I` / `O`	Zoom In And Out
`Shift` + Arrow	Rotation Around Axis
`R`	Rotate View 180°
`B`	Mark Node as New Branchpoint
`J`	Delete Branch Point
`S`	Center Active Node
`F`	Forward Without Recording Waypoints
`D`	Backward Without Recording Waypoints
`Del`	Delete Node / Split Trees
`Shift` + `Space`	Delete Active Node, Recenter Previous Node
`Shift` + `Alt` + Left Click	Merge Two Nodes and Combine Trees
`Shift` + `Ctrl` / `Cmd` + Left Click	Delete Edge / Split Trees

Volume Mode¶

Key Binding	Operation
Left Mouse Drag or Arrow Keys	Move (Move Mode) / Add To Current Segment (Trace / Brush Mode)
Right Click	Bring up context-menu with further actions
`Shift` + Left Click	Select Active Segment
`Ctrl` / `Cmd` + Left Mouse Drag	Add Voxels To Current Segment while inverting the overwrite-mode (see toolbar for overwrite-mode)
`Ctrl` / `Cmd` + `Shift` + Left Mouse Drag	Remove Voxels From Segment
`Alt` + Mouse Move	Move
`C`	Create New Segment
`Ctrl` / `Cmd` + `I`	Copy Segment ID Under Cursor (add `Alt` to copy the mapped ID)
`Shift` + Mousewheel or `Shift` + `I` / `O`	Change Brush Size (Brush Mode)
`V`	Interpolate current segment between last labeled and current slice

Note that you can enable Classic Controls which won't open a context menu on right-click, but instead erases when the brush/trace tool is activated.

Key Binding	Operation
Right Mouse Drag	Remove Voxels
`Ctrl` / `Cmd` + Right Mouse Drag	Remove Voxels while inverting the overwrite-mode (see toolbar for overwrite-mode)

Proofreading (Only for Paid Plans)¶

To use proofreading, first activate an agglomerate mapping for the volume layer and then switch to the proofreading tool.

General Shortcuts:

Key Binding	Operation
`M`	Toggle Multi Cut Tool

If Multi Cut Tool is activated, the following shortcuts are available:

Key Binding	Operation
`Enter`	Perform Multi Cut
`Esc`	Clear Partition Selection of Multi Cut Tool
`Ctrl` / `Cmd` + Left Click	Add Segment to Partition One for Multi Cut
`Ctrl` / `Cmd` + `Shift` + Left Click	Add Segment to Partition Two for Multi Cut

Orthogonal Viewport¶

Key Binding	Operation
Left Click	Activate Segment of Agglomerate for Proofreading Actions
`Shift` + Middle Click	Import Agglomerate Tree of hovered agglomerate
`Shift` + Left Click	Merge with Active Segment
`Ctrl` / `Cmd` + Left Click	Split from Active Segment

3D Viewport¶

Key Binding	Operation
`Ctrl` / `Cmd` + Left Click	Activate Segment of Agglomerate for Proofreading Actions

Tool Switching Shortcuts¶

Tool switching is a multi-step shortcut. First press Ctrl / Cmd + K, release the keys, and then press the letter assigned to the tool.
Ctrl / Cmd + K is not needed for cyclic tool switching via W / Shift+W.

Key Binding	Operation
`W`	Cycle Through Tools (Move / Skeleton / Trace / Brush / ...)
`Shift` + `W`	Cycle Backwards Through Tools (Move / Proofread / Bounding Box / Pick Cell / ...)
`Ctrl` / `Cmd` + `K` , `M`	Move Tool
`Ctrl` / `Cmd` + `K` , `S`	Skeleton Tool
`Ctrl` / `Cmd` + `K` , `B`	Brush Tool
`Ctrl` / `Cmd` + `K` , `E`	Brush Erase Tool
`Ctrl` / `Cmd` + `K` , `L`	Lasso Tool
`Ctrl` / `Cmd` + `K` , `R`	Lasso Erase Tool
`Ctrl` / `Cmd` + `K` , `F`	Fill Tool
`Ctrl` / `Cmd` + `K` , `P`	Segment Picker Tool
`Ctrl` / `Cmd` + `K` , `Q`	Quick Select Tool
`Ctrl` / `Cmd` + `K` , `X`	Bounding Box Tool
`Ctrl` / `Cmd` + `K` , `O`	Proofreading Tool
`Ctrl` / `Cmd` + `K` , `I`	Line Measurement Tool
`Ctrl` / `Cmd` + `K` , `A`	Area Measurement Tool

Quick Select Preview¶

When Quick Select preview mode is enabled:

Key Binding	Operation
`Enter`	Confirm current Quick Select
`Esc`	Cancel current Quick Select

Note that you need to first press Ctrl / Cmd + K, release these keys and press the suitable number.

Key Binding	Operation
`Ctrl` / `Cmd` + `K` , `1`	Switch to small brush
`Ctrl` / `Cmd` + `K` , `2`	Switch to medium sized brush
`Ctrl` / `Cmd` + `K` , `3`	Switch to large brush

Key Binding	Operation
`Shift` + Click on a mesh in the 3D viewport	Move the camera to the clicked position
`Ctrl` / `Cmd` + Click on a mesh in the 3D viewport	Select the mesh and its segment ID

Agglomerate File Mapping Skeleton¶

The following binding only works in skeleton/hybrid annotations and if an agglomerate file mapping is activated.

Key Binding	Operation
`Shift` + Middle Click	Import Skeleton for Selected Segment

This video demonstrates an annotation workflow using some keyboard shortcuts:

Classic Controls¶

Note that you can enable Classic Controls in the left sidebar. Classic controls are provided for backward compatibility for long-time users and are not recommended for new user accounts. Hence, Classic controls are disabled by default, and WEBKNOSSOS uses a more intuitive behavior which assigns the most important functionality to the left mouse button (e.g., moving around, selecting/creating/moving nodes). The right mouse button always opens a context-sensitive menu for more complex actions, such as merging two trees. With classic controls, several mouse controls are modifier-driven and may also use the right-click for actions, such as erasing volume data.