Search Engine Manager window bug

[_yup_]

Working on Search Engine Editor extension, I found a bug of the Search Engine Manager window.

If this window contains quite a lot of engines (more then 10), and a user tries to reorder them (by dragging or by "Move Up"/"Move Down" buttons), then a whole list jumps up, so selected item (if it is below row 10) becomes 10^th visible, and all engines below 11^th becomes non-clickable.

If the user uses dragging, then bottom engines become non-clicable after next opening of this window (mostly). If he uses "Move Up"/"Move Down" buttons, this happens immediately.

In this example after reordering no one engine below 11^th row ("Mycroft Project") can be selected by a mouse click:

EngineManager.png

Click on row 11 results in scrolling a whole list one row up:

EngineManager2.png

- so row 11 becomes row 10.

And any sequential click on [visible] row 11 results in scrolling one row up more:

EngineManagerAll.png

Notice that after list scrolling the vertical scroll bar does not appear, so the user may decide that top engines get deleted from the browser.
(The list can be scrolled down by a mouse wheel or by the keyboard "UP" key though. Also bottom engines can be selected by keyboard navigation.)

If the bug has been triggered, then closing and re-opening the window does not help (mostly).
The window restores its normal functionality after resizing (in any direction - horizontal or vertical) - until the next reordering.

The bug was inherited from the Mozilla (as it is also present in the original Seamonkey browser).