First, THANK YOU for including this feature!
Anyway I have found one tiny issue with the group header when dealing with toggling the hidden state of columns. If you group together 10 columns all in the same group with the group title centered like this:
| GROUP TITLE |
| col1 | col2 | col3 | col4 | col5 | col6 | col7 | col8 | col9 | col10 |
Then you proceed to hide 6-7 of these columns, the group title is no longer centered over the visible columns, and in some cases can even become no longer visible. It appears that the columngroup title header is evaluated based on all the columns being visible (width, text position). Is it possible that the columngroup title header can be evaluated based on the visible columns? I understand this might be a little confusing I can provide more clarification if needed.
