While animating I use quite alot
shift+4 and shift+5 to insert and remove frames at a specific point in a timeline
recently I discovered that behaviour is different for layers with key frames and layers with tween frames
For example if I place my cursor on frame 5 (look attached image) and I press shift+4 a new frame is inserted, the key frame 12 will move to 13 but on the layer 2 the tween frame 15 will not move to 16.
Same if I shrink with shift+5
