One of the next versions of FocalBlade will also let you press down the Space key to move the image in the preview. That's how you can do it in Photoshop.
Pierre Beziers wrote:It is possibe whith pressig the right butom off the mouse, and moving over the preview.
Neither holding the right mouse button and dragging nor holding down the alt key and pressing the left mouse button is working for me. The only thing that happens is the split screen disappears and the entire image is shown in the preview window.