www.roarie.cat/kaeditor/documentation

On UI elements (from top to bottom; left to right: canvas; palette, brush, tools, menu)
<CTRL> <ALT> <LMB> (while dragging) Make UI element floatable & move
<CTRL> <RMB> (while dragging) Resize UI element
<CTRL> <ALT> <SHIFT> <LMB> Restore UI element as non-floating and at its original position
<CTRL> <ALT> <RMB> Restore original UI element size
These keyboard commands work in brush mode (square, circle, cross):
[ Increase brush height and width
] Increase brush height and width
<CTRL> [ Decrease canvas width
<CTRL> ] Increase canvas width
<CTRL> <ALT> [ Decrease canvas height and width
<CTRL> <ALT> ] Increase canvas height and width
<CTRL> <SHIFT> [ Decrease canvas height
<CTRL> <SHIFT> ] Increase canvas height
On brush:
<LMB> Erase cell
On canvas:
<CTRL> <LMB> Draw with foreground colour
<CTRL> <RMB> Draw with background colour
<SHIFT> <LMB> Draw line from last position to cursor
<ALT> <LMB> Set foreground colour from cell at cursor position
<ALT> <RMB> Set foreground colour from cell at cursor position
On custom brush:
<SHIFT> <LMB> Delete custom brush
On palette:
<LMB> Set foreground colour
<RMB> Set background colour
<CTRL> <LMB> Set background colour for block elements in palette
<LMB> (on block element) Set foreground to block element with combined colours
<RMB> (on block element) Set foreground to block element with combined colours (reversed)
Fill tool:
<LMB> Fill with foreground colour
<RMB> Fill with background colour
Underline tool:
<LMB> Set underlined attribute
<SHIFT> <LMB> Remove underlined attribute