With a current nightly build of Firefox, you sometimes see ghost cursor(s) appearing in the urlbar (also in combination with selecting something from autocomplete. Another situation where ghost cursor appear is in Chatzilla when you have sent a message to a channel (Chatzilla uses a XUL textbox). In Chatzilla the ghost cursor only seems to appear when typing a string which some minimal length (together with the nickname maybe?). I'll attach a screenshot showing this ghost cursor. This probably regressed between 2005-08-12-05 and 2005-08-13-05.
Related to bug 304383?
Yeah could be related, though the regression range would not match (maybe another bug being exposed through a new checkin?) and i'm quite sure that the range is correct.
Does the patch in bug 304383 help?
Yeah looks like the patch there fixes it (also i still wonder why my regression range is different :).
*** This bug has been marked as a duplicate of 304383 ***