Questions about Xrandr for GUI development

[Alberto Milone]

Hi, I am developing a GUI  for Xrandr in pyGTK and I would like to know
a few things:
1) what does * mean?
2) what does + mean?
3) what does *+ mean?

I refer to the output of xrandr such as the following:

VGA disconnected (normal left inverted right)
LVDS connected (normal left inverted right)
   1280x800       59.9 +
   1024x768       60.0
TMDS-1 connected 1680x1050+0+0 (normal left inverted right) 0mm x 0mm
   1680x1050      59.9*+
   1280x1024      75.0     59.9


Thank you in advance

Alberto Milone