If you click into a slice and paint e.g. a certain pixel and then move the mouse wheel in order to slice through the image without moving the mouse then nothing happens when you just click to paint another pixel.
The problem is that the paint tool is working on a working slice. The check if the current working slice has changed is only performed after mouse movement.
[8aeab2]: Merge branch 'bug-12060-painttool-does-not-react-after-scrolling'
2012-05-31 10:24:13 Andreas Fetzer [fef76b]
Fixed bug which caused painttool not to react on mouse click
Removed static local variable which made it neccessary that the mouse cursor
had to be move (even a little bit) before paint tool was able to react on a
simple mouse click. Painttool logic also works without this variable.