VNC single click opens file

Using Avalanche on a pi Qube (5.29) to access a pi 4te (5.28) I can’t drag files or directories because as soon as an icon is clicked it opens the file or directory. Ie behaving like a double-click.

The mouse behaves normally on the Qube screen.

I have tried changing drag delay parameters for the mouse configuration but to no avail.

ISTR reading somewhere something about a single click open but can’t find a reference. Is there some way of changing this behaviour?

Follow up with more info.

I have found the setting for click/hold open in the filer settings and turned it off but it does not fix the problem.

It looks as if the problem is hardware specific.

Pi 4te running VNCServer
connected via Avalanche on ARMX6 no problem
connected via Avalanche on Qube YES problem
connected via RealVNC on Mac Mini M1 no problem