Toolbar items with variations open a menu on long press. But they will also open immediately on drag. The amount of distance it considers a drag is about two pixels. Tablet pen users generally move more than that while selecting items so the menu almost always pops out. This PR uses the correct drag distance per pointer type, and uses the position of the start of the drag instead of the last reported position. Pull Request: https://projects.blender.org/blender/blender/pulls/135677