Let me first start by saying I know GCC4TI is old and abandoned. I still use it everyday however. I posted already about the taskbar buttons not combining in a group. You can see that post here Groupy Taskbar buttons not grouping.
In addition however there are some other odd quirks. when switching tabs you can see an additional taskbar button displayed for a split second before disappearing. Also when minimizing one of the grouped windows it is removed from the group instead of minimizing the entire group. It does get placed back into the group on restore. Maximize and restore (from max) works on the whole group however.
After switching tabs back and forth a few times I notice that the active tab displays a single taskbar button on all desktops except the one the window is actually on. There it still shows all buttons from the group. Clicking on the single button (from a desktop it isnt on) will cause a desktop switch to the one its on. Sometimes changing the tab once more will remove the extra button from the other desktops.
Below is a video demonstrating these effects.
Here is a link to TIGCC Where you can download the binaries and/or the source. Note: GCC4TI is a fork of TIGCC whereas the IDE itself hasn't changed much.
There are also some weird oddities with WindowBlinds and GCC4TI as well but I'll post that to the WB section.
On an unrelated note how does one tag other forum users?