Selection in Crowded Parts of Diagram
If you want to select an element that is difficult to access - you can only right-click near that area and choose the Select submenu from the context menu. It will let you choose from a list of nearby and stacked elements. If you click on the menu item for the desired diagram element, it will be selected in the diagram editor. This way, you do not need to try to hit an exact place in a few pixel areas.