Custom button with left right and middle mouse click actions

in one of the somewhat recent DOpus updates my configuration got reset and I had no backup.
It was easy to re-create most of my preferences, except for custom button behavior.
I used to have a few buttons that did three different actions, depending on which mouse button pressed them: left - open Visual Studio, right - run the latest build exe, middle - open a new tab in DOpus at the location of the .sln file.
Now I can't find anymore how to set that theeway mode up again.
Please advise.

It's called a Multiple Function Button.

Did you install the 13 beta? Any modified toolbars will be backed up automatically if that was what changed them. The backups should be listed in Customize > Toolbars.

OTOH, smaller updates shouldn’t touch existing toolbars at all.

Ah, I had missed the "add button" after converting it to the Multiple Function Button type.