Lock Front/Top/Left views from entering User view when dragging mouse Is there a way to lock the top/bottom, left/right, front/back views (ortho or perspective) rotation so that these views don’t accidentally move out into the user view when dragging with the mouse ?
note: this is particularly useful (to me) when using these views to do (blackboard/whiteboard) annotations and I don’t want to accidentally have these  top/left/front views be rotated out of their orientation when I drag the mouse.
Well. it turns out there is an add-on for this already that lets you lock/unlock any 3D view (top/bottom, left/right, front/back views.. and also the user view.. in orthographic or perspective modes). The add-on is available on Blender Market:
https://blendermarket.com/products/wlock-pro---an-addon-which-allows-to-lock-3d-view-rotation