Display Priority
Basically, the order in which elements are inserted also determines the order in which they are displayed in your software. For instance a filled rectangle which is drawn over text that was inserted previously, will cover the text, which is then no longer visible. This default can be changed subsequently with the 
button for display priority, which is always shown in the toolbar when an element is selected. This enables you to specify the order in which elements are displayed to meet the particular requirements, e.g. inserting text over a filled rectangle when creating a title block.