<element type="Text" xAnchor="Panel.Left" yAnchor="Panel.Top" widthDock="X:Panel.Right" heightDock="Y:Panel.Bottom" font="Segoe UI" style="Regular" size="35" fg="0,255,0" align="Middle.Center">Middle.Center</element>
I've tested the following using the element above.
align="Top/Middle/Bottom/Left/Top.Left/Top.Center/Top.Right"...element is positioned top left.
align="Middle.Left/Middle.Center/Middle.Right"...............................element is cut off at the top left of the screen (https://i.imgur.com/zeav0JI.png).
align="Bottom.Left/Bottom.Center/Bottom.Right"............................element is out of bounds. Does not appear anywhere on screen.