Dashboard opens but mondo solitaire widget is blank green rectangle. Also, mondo solitaire does not appear in current Apple widget website. I seem to have lost a friend.
Two years after the problem was posted, but what the hey, better late the never they say.turns out that OS X 10.8+ has an issue with a space in the directory name.
when you download mondosolitarie.wdgt.zip unzips into
"mondo solitaire.wdgt" - directory with a space in it
Just remove that space, e.g. -> mondo.wdgt or mondosolitaire.wdgt
and then install the widget - default game will be selected. Also selects for table, card, and card backs will be again available.
OS X 10.9
I have registered to reply to this problem.
I too had the same problem after upgrading to ML this day. The fix is to click on the i symbol bottom right hand corner of the green panel - you will need to move your cursor over that area for the symbol to show up. then in the Games drop down menu choose a different game, click Done. Now repeat the process but this time choose the game you want. The game we had problems with was Klondike game (2).
Hope this helps.