Today: how to zoom in and out in Kdenlive's project and clip monitors. The mouse wheel normally simply seeks back and forward when the mouse is in either the clip or project monitors.
But, when holding both Shift+Ctrl when wheeling in the monitors then zooms into the frame and out again.
Extremely useful when dealing with slightly more involved affine transitions with several key frames and each such frame needs to be precisely placed on screen, for instance, for simple animations.