When setting up a panel layout where two panels are adjacent to each other (for example a panel on the top edge and one on the left edge of the screen) there are two minor usability problems:

1. It is quite fiddly resizing / moving the left panel so that it fits exactly into the space between the top panel and bottom screen edge. When resizing / moving the panel it should snap to the screen edge / other panels

2. The panel shadow of the left panel overlaps the top panel. Similar to how the panel shadow gets deactivated when the panel is on one edge of the screen it should get deactivated when a panel is next to another panel (there should be no gap on the point where two panels touch each other).