[BUG] Cannot collapse folder with Contour mouse dedicated double click button

I have a RollerMouse Free2 ergonomic mouse: http://ergo.contour-design.com/ergonomic-mouse/rollermouse-free2

The middle button is configured so one (1) click gives a double click. If i create a new backup job in TI2016 and use that button to double click on a folder the subfolder never collapse. After some testing i have noticed that TI2016 ignores a double click if the two clicks are "beamed out" too fast. So if i slowly click twice on the right click button the folder collapses in TI2016.

On the attached image mouseproperties.png you can see that the double click speed is set to the slowest setting. Setting it to any other value makes no difference.

I was on the beta for TI2016 but did not beta test build #5518. In earlier betas i had no issues to collapse folder with the double click button on my RollerMouse Free2 mouse.

This is a total show stopper since selecting what files and folders to select takes to long time. I have no issues in other apps with the double click button. If i use that button to click on a HDD in Explorer all of it´s subfolders are presented to me. One more click with that double click button makes all subfolders de-collapsed. So the mouse works perfectly with all apps but TI2016.