Inventor undo isolate option grayed out

[swforge1]

Hi all,
Anyone seen an instance where the undo isolate option is not selectable in an assembly? Have seen it a couple of times in assemblies where after isolate is used, the undo isolate is grayed out. I have gone thru and manually made all visible to work around
Inventor 2010 latest sp
Thanks

 

[mcgyvr]

Yes had it once or twice (probably around 2010 version or so). Are you up to date on hotfixes/service packs?