There is a problem with grouping of columns. I have put a small sample project. On 1.10.1007 all works normally. This problem has started to arise on service release 10.1.2027.
No, there is no workaround.
Do you have an Workaround?
This is a known bug and it will be corrected in the next service release, which is scheduled to go out at the beginning of July.
Infragistics Service Releases
I have got the same problem...
the Bug disappear's after the DataSource gets applied a second time when the Grid is already shown.
That's a CRITICAL BUG for us because lot's of Customer's are using this Function!
I have put screenshots.