Comment 7 for bug 1372151

But I can keep giving you clues, I guess.

Draw a star with Star tool.
Use Paint Bucket to fill.
Do a few edits to the fill path (scale, skew, change color again via palette).
Try Undo.
Redo remains grayed out UNTIL I get back to the step where I made the original fill with the Paint Bucket tool.
When I undo that step, the Redo button becomes activated, and I can re-fill the star using Redo button.
However, I cannot Redo beyond that point (can't redo the scale, skew, 2nd color change).

Weird, huh?