Ronning out of Undo

[TerryRitchie]

While the Undo is extremely useful for recovering from a faux-pas (and that's quite frequent for me), there doesn't seem to be
 an indication when you've used up all your Undo's. When this involved back-tracking over a number of  changes, you may reach 
the limit, and no changes are made. This can be hard to see with a long programme, as  changes may not be obvious in the IDE.
Is there, or can there be, a "Limit of Undo" message?

For now you could increase the history buffer to 2000MB (2GB) so you'll probably never reach the limit.

Options menu -> Backup/Undo...

I use a paint program that describes what you want. When I reach the limit of the buffer it pops up a message stating that no further undo actions can be recorded.