1. Use the cursor keys while working with an animation

 

As long as you hold down the 'Left-Key', the frame before the current frame of the animation is displayed in the editor. As long as you hold down the 'Down-Key', the current frame, and as long as you hold down the 'Right-Key', the frame after the current frame is display in the editor.

Example: You are drawing a frame for an animation. Hold down the 'Left-Key' and you can compare the previous frame with the new frame very easily.

Other possibility: In a complete animation click on the second frame. Now click on the symbol 'Put to Editor' to display this frame in the editor. If you now hold down the 'Left-Key' and then the 'Right-Key' (and then in reverse order) you can check if the animation is smooth.