I have the windows powertools installed that allows me to see a small version of tasks when I use the ALT+TAB task switcher in WindowsXP.

One of the tasks is apparently something called "RD Tabs Resource Manager" which doesn't come up when I switch to it. The small version of it appears to contain some kind of error: "While attempting to complete the last operation, RD Tabs ran into an error while trying to allocate resources. The specific error returned was 'Error creating Windows handle' which indicates that Windows is low on Desktop Heap memory..." There is more describing what the error means, but the small preview is about an 1.5" square, so you can imagine how small the text is (font size 2?)

I'm using RD Tabs version 2.0.13.

There's no error, actually.

Let me explain what the Resource Manager is for and why.

The Microsoft Remote Desktop control is very heavy-weight. It consumes many window handles. Windows only has a finite number of window handles and desktop heap memory available. When a very large amount of tabs are open (in excess of 80 or 90) you run the risk of running out of window handles or desktop heap. This is not unique to RD Tabs. Even Microsoft Excel, when too many documents are opened, can run out of Window handles (I've made it happen lol).

Microsoft introduced a whole suite of new development tools for Vista as part of the Windows Presentation Foundation, which uses ONE window handle (and far less heap) for each form an application opens. This will, in the future when it is more widely adopted, prevent this problem from ever occurring. It will also preserve backwards compatibility with non-WPF applications (which is why they can't just arbitrarily increase the number of available handles or the size of the heap).

Anyway, when Windows runs out of these resources, no window, dialog, or control can be opened (INCLUDING error messages telling you it can't open anything). What the RD Tabs Resource Manager does is sit in the background and wait for this to happen. If Windows runs out of desktop resources, it immediately frees about a dozen pre-allocated handles (along with the associated heap) and initiates the Framework Garbage Collector to help release pressure on the system. It also sets a flag that prevents RD Tabs from opening any more tabs than are currently open or cached, so you don't crash RD Tabs. At the same time, the window you see the miniature version of is displayed to the user (it is normally supposed to be hidden, but apparently the powertoy brings it into view as a thumbnail for you), to inform the user that resources are low, and that closing down applications is the only way to release pressure on the system.

So, to sum up, nothing to see here, move along. ;-)

Meanwhile, I'm going to see if I can mask the error message from thumbnail views so it doesn't freak people out.

P.S. thanks for the heads up.