I use a Mac together with Spaces which permits more than a single desktop.
I have a problem though, whenever I click on let's say a new browser window (loading firefox), spaces jumps to a desktop which already has firefox open. Is it possible to make osx open a new firefox window (or any other application), if it does not exist in the current desktop, instead of moving to the desktop?
Note that the preference has moved in Lion. It's now under Mission Control.
Try unchecking the checkbox at the bottom in System Preferences » Exposé & Spaces.
Remember to set your browser to open links in new windows instead of new tabs of existing windows.
I just found a great and easy solution for FireFox which lets you open links a a new window in the current space: Use the FireFox Add-On "TabMixPlus". In the TabMixPlus-settings, under "Links", there is an option called (translated from german) "for links from other applications, use different settings", and there you can choose "New window". For me, when I click on a link in a PDF file or in a message in Thunderbird, this now opens a new FireFox window in the current space! TabMixPlus is available via the Add-Ons menu in FireFox, or look at http://tmp.garyr.net/
