Dear D5 Team,
I don’t know if this is a wide know issue by now,
But since the latest 2 or 3 updates to the D5 Plugin from ver. 3.8 to 3.9 to 4.0 making a group or exploding a group or doing anything in sketchup generates a very weird and strange behavour, generating crashes, and all sort of problems, so after testing many things (even thougth about formating my pc because why not? Thankfully I didnt), like opening a new file and copy only a single component and exploding it, didnt work still took ages to do so, I decided also to Uninstall entirely Sketchup and reinstalled again (Including all the plugins) and guess what! I have found that after deleting the D5 Plugin Ver. 4.0 entirely from the Sketchup and also from the installation folder, does solve the problem.
I hope you guys can check this and solve the issue, not sure what is the problem itself.