Comment 4 for bug 781397

Except for inkscape freezing,
this sounds very similar to the popup i'm getting.

When clicking on an item in the help menu that opens a webpage,
then two popups open in the center of the inkscape window,
and the webpage opens in the browser.

The first popup says:
'Keys and Mouse Reference' working, please wait...
[Cancel]

the text between the '' signs refers to what was clicked.

The second one says:
Inkscape has received additional data from the
script executed. The script did not return an error,
but this may indicate the results will not be as
expected.

(process:9189): GLib-CRITICAL **: g_slice_set_config: assertion `sys_page_size == 0' failed
[OK]

If the second popup is moved then one can see that the first one is still open behind it.

If one clicks OK on the first popup,
then they both go away, and inkscape works fine.

Tested with:
r12833 on linux mint 15 cinnamon 32bit
Firefox v25.0.1 is the default browser.