I use this version : datacrow_3_9_26_zipped.zip
This is on Windows7 64bit.
Open this menu : Settings-->Settings.
Go into any submenu (for example Enabled Modules), then click on "Save".
The GUI font is automatically changed, and become very difficult to read.
Resetting the menu "Settings-->Look and Feel" doesn't help.
I also tried Settings-->Font-->Default, but it didn't help.
Then I changed the Font several times, until I found one that looked like the original.
It seems to only bug on windows, not on Mac OS X.