I fixed the glitch that was causing the overly rounded corners in Mountain Lion. To update the widget, just head on over to the widget page and click the download button.
There are two more issues I haven’t been able to solve though.
Gatekeeper
When you download the dashkards.zip file and unpack the contained widget file, you might get an error in Mountain Lion stating that your security settings won’t allow installing the widget. This is due to the fact that the dashkards widget is not signed with an Apple Developer ID, which is mandatory for apps that are not from the Mac App Store. You can still install the widget, but rather than double-clicking it, right-click (or ctrl-click) it and select Open from the contextual menu.
Widget back display problems
For reasons I haven’t yet been able to investigate, the list of checkboxes on the back side of the dashkards widget that let you select which cheat sheets to display or hide does not display the app names next to the checkboxes. I’m still trying to find out what is causing this, but so far I don’t have a solution.
Tweet
Hmm - the version of the widget I’m downloading from the location you linked still cuts off the corners…
Sorry about that, uploaded the file to the wrong folder. Please re-download the widget, should be fixed now.
I’m still seeing the rounded corners too, downloaded multiple times and even tried deleting the old one…