undo command ("u") sometimes stops working

ctrl+Y stops working too in that situation. This is pretty annoying and dangerous when I am doing large block code change.

Please take a look. Thanks!

undo/redo broken

i can confirm this. really an ugly issue. i'm using cdt and it's editors in eclipse and redo/undo is very unreliable.
once it is broken, it messes up the text in the editor. i resorted to not using it at all which seems really wrong!
why not use the normal eclipse undo/redo functionality?
JFTR: once the undo/redo bug shows up i have to close the editor to "normalize" the behavior.

Yes, and the odd thing is

Yes, and the odd thing is control-Y (command-Y for me on mac) doesn't seem to come back after it's screwed up. Pretty bad. Love the plugin though so not complaining, but if it happens too often I'll have to ditch it. (Happening for me on eclipse Build id: 20090920-1017 - one of the latest, not sure what exact version since can't figure out how to tell? Happened to me just now again while editing an xml file.)