PixmapButton - Undo/Redo

[zonkmachine]

Undo/redo of PixmapButton shows erratic behavior. A single press of a PixmapButton seem to indicate that undo/redo isn't implemented for this class but consecutive presses will register but it's glitchy.

Example one:
Press mute button on a track and then press <Ctrl+z> or use the edit menu function. The action isn't reverted.

Example two:
Press mute button on a track twice followed by two 'undo' actions. The second undo will change the state of the button.

Example three:
With two unmuted tracks in the song editor do the following.
Press the mute button on the first track four times.
Press the mute button on the second track four times.
Press <Ctrl+z> once. Nothing happens.
Press <Ctrl+z> three times. The second track will change state to muted.
Press <Ctrl+z> once. Nothing happens.
Press <Ctrl+z> three times. The first track will change state to muted.

[musikBear]

Confirming for win32 RC8
Good find / first issue!