When operating on MacOSX, I have constent issues with the mac trackpad getting stuck with clicking and dragging. Quite often it gets confused between right clicking, or left clicking, or holding the button down, or scrolling. Trackpad operation in all other applications besides Unreal Engine 4 work perfectly…
I have the exact same issue, this makes it impossible to work in the editor without a mouse.
Sounds a lot like the issues reported in:
It would seem that the 4.4 release had changes that affect mouse/trackpad operation and we have a fix ready for a 4.4.1 update.