That's very strange, in my MacBook with 10.6 it works normally. Could you describe your system so that I can find the bug? Which Mac OS X version, any special hardware, maybe screen resolution, is it 64-bits?

To increase/decrease the magnification you can use the + and - keyboard keys (via shift if necessary).

There are instructions, in the system tray icon in the Help section is shows a PDF with the instructions.

The fact that you're using the words "system tray icon" suggests Mac users shouldn't waste their time.

This is one of about 4 magnifiers, 3 screen readers, 3 on-screen keyboards, and yes, a calculator, and a bunch of other apps that our Disability Resource Center makes us put on our Windows lab computers, in spite of the fact that they duplicate the functionality of each other _and_ the system, and in spite of the fact that they have no idea whether anyone even needs/wants/uses them. But we get bullied into it because it's the DRC, instead of actually finding out what our disability users actually need. Thank gawd they haven't figured out there's a Mac version.

Don't install unnecessary software. Turn on Universal Access and be done with it.

Mac Pro E 2008 OS X Lion 10.7.2

Ok, thanks a lot for the info =) Indeed I just found a 10.7 computer here and it doesn't work in 10.7, but it works in 10.4 to 10.6 normally. Clearly Apple changed something here which broke the magnifier ... I think it broke the screenshot taking code.

The next version should use a different Lazarus backend, probably LCL-Cocoa or LCL-CustomDrawn-Cocoa and then I will be careful to verify that the screenshot taking part of the new backend works properly in 10.7 too. I'll post a new version when ready.