Commit [a5173d] default Maximize Restore History

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.

nyamatongwe nyamatongwe 2013-04-17

changed src/Document.cxx
src/Document.cxx Diff Switch to side-by-side view