I have a non-rectangular desktop.  It has three monitors arranged in a square with no monitor in the upper left hand corner.

When I open the "System Activity" dialog, either with Shift-Escape or by running "systemmonitor" from the command line, the dialog will always (and I really do mean 100% of the time) open in the place where I have no monitor.  I can click on the entry in the taskbar, navigate down to the Move option and drag the window onscreen to see it.

I tried setting up a kwin rule to ignore the initial placement for that window (and always put it under the mouse, or on the primary monitor, or something) but I can't seem to get that to work for whatever reason.

This isn't the only window that usually opens offscreen, of course.  Generally, though, it's just transient dialogs that do it.  While a kwin option to prevent things from opening offscreen would probably be a good idea, I figured I'd file file a ticket against each individual application I run across.  Absolute positioning is generally a bad idea unless you're just restoring the last position where the dialog was closed, but if you're going to do it, at least clamp to the active portion of the desktop and not just to the bounding rectangle.

Reproducible: Always

Steps to Reproduce:
1. Have a weird non-rectangular desktop, with no monitor in the upper left-hand portion.
2. Open the system activity dialog.
3. Notice that you can't see said dialog because it opened offscreen.

Actual Results:  
Dialog opens where there's no monitor to display it.

Expected Results:  
Dialog opens someplace where a monitor exists to display it.