The font tester is started with the gpUITester command with the file name of the UI properies as an argument. For example:
gpUITester uiABC.propertiesIt will bring up the subject UI window (in this case an A/B/C test UI window:
The window will show the control and answering panels of the subject UI. All the features of subject UIs cannot yet be tester with the UITester tool (more features will be added later).
To quit, close the window using the close-button in the top left.