History panel

A Photoshop-style list of every step you have taken in the project: click a row to jump straight to that state.

History shows one row per committed step, oldest at the top, newest at the bottom, going back to the moment the project was opened. It is a straight read of the same undo stack that Ctrl+Z and Ctrl+Y walk, so anything one of those keys can reach, a click here can reach directly.

Opening it#

Open it from Window ▸ History. It is off by default.

Reading a row#

Each row carries a small coloured chip for the kind of change it was: green for adding a layer, red for deleting one, blue for a transform, amber for a keyframe, and so on through style, effects, colour, physics, cells, bones, mesh, selection, variants and reordering. The current step is highlighted; rows before it read in a lighter grey, and rows after it (the ones a redo would reach) are dimmed but still fully clickable.

Row labels describe what changed in plain terms: Add shape, Delete group, Move, Rotate, Scale, Opacity, Blend mode, Keyframe, Color, Reshape, Cell, Paint, Erase, Fill, Smudge, Cut path, Bone, Mesh, Physics, Variant, Reorder, Canvas size and more, down to a generic Edit when nothing more specific applies. Every row carries an icon; none is ever blank.

Most labels are derived by comparing the before and after states, so they stay right even when a command changes. A handful of operations look identical to that comparison and name themselves instead: Align, Distribute, Fill, Smudge, Cut path, and the bone-binding family: Bind vertices, Unbind vertices, Auto weight, Mirror weights, Paint weights and Link/Unlink layer to bone.

What counts as a step#

Anything that would otherwise need an explicit undo (adding, deleting or reordering a layer, any drag that changes a value, every keyframe you set, every stroke you paint) becomes its own row. Selection changes are deliberately included too, and each says which kind it was: Select layer, Select layers, Select all layers, Add to selection, Remove from selection or Deselect. If you only want to step back through content changes, expect to pass through a few of those along the way.

A pixel selection is its own kind of step, kept separate from layer selection and marked with the marquee icon rather than the arrow: Select pixels the first time a marquee or wand commits, Modify selection for Add, Subtract, Intersect, Expand, Inset, Feather and Invert, and Deselect pixels when the mask is cleared. Undo brings a mask back exactly as it was, so a selection you lost by mistake never has to be redrawn.

Jumping between states#

Click any row to jump to it in one action: Celas Studio works out whether that means undoing several steps or redoing several, and gets you there in a single click rather than one keystroke at a time.

Undo depth#

How far back the list reaches is set by Undo Levels in Preferences, 10 to 500 steps, defaulting to 100. Once you pass that many steps, the oldest ones drop off the top of the list and can no longer be reached, from this panel or from Ctrl+Z.