Disallow undo and redo when not collecting undo as it is likely that the document is not in the state at the end of the undo history and performing undo will not be able to return to a previous state.
Disallow undo and redo when not collecting undo as it is likely that the document
is not in the state at the end of the undo history and performing undo will not be able
to return to a previous state.

rhaberkorn/scintilla-mirror,rhaberkorn/scintilla-mirror,rhaberkorn/scintilla-mirror,rhaberkorn/scintilla-mirror,rhaberkorn/scintilla-mirror,rhaberkorn/scintilla-mirror,rhaberkorn/scintilla-mirror,rhaberkorn/scintilla-mirror