Bugfix #25570

The tool-redo depends on a working undo system, so it can rewind
a step and then redo operator with new settings. When a user
disables undo, this won't work.

Now the properties for redo operator (toolbar, F6) will grey out
when a redo isn't possible.

source/blender/editors/include/ED_sculpt.h

@@ -51,5 +51,6 @@ void ED_keymap_paint(struct wmKeyConfig *keyconf);
 
 int ED_undo_paint_step(struct bContext *C, int type, int step, const char *name);
 void ED_undo_paint_free(void);
+int ED_undo_paint_valid(int type, const char *name);
 
 #endif