Hi Michel, it sounds like a bug that I do have fixed for the next upcoming beta - the bug is triggered on Mac if you do a 2-finger drag but start the initial gesture with one finger in a different window than the viewport (the view controls panel is actually a separate window), then drag over and add the second finger inside the viewport without ever having lifted up the first finger.

If it is the same bug then it should be fixed in the next beta release, please let me know if it isn't. I'll be trying to wrap up the next beta in the next week or so.

- Michael