Unable to turn off FCKEditor for l10n_client textarea

I have just installed this fantastic module in a site which will have to support 3 languages. Unfortunately, there seems to be some sort of interface bug with the items, which makes using the module quite difficult. This is reproducible both in Safari and Firefox.

When I access a page which requires translation, and click on the 'Translate Text' link, the panel opens up on the bottom of the window. No problem there.

Inside the panel, however:
1) the 'search' field gets clipped by the middle grey column (the one that shows the contents of the unstranslated string)
2) in the "Translation to " column, under the usual translation input field - the one where we are supposed to type in the translated string - there seems to be a SECOND input field, about 50% narrower than the top one. I cannot find any documentation about the function of this second field, and it only seems to show up on some pages, and not in others.
3) the buttons ("save translation", "copy source" and "clear") are all sunk halfway out of the window. If I tab to focus on one of the buttons, the entire interface moves up, and half the top tab ("page text", "source", and "translation to ***") gets clipped off.
4) If I type something in the search field, then delete it, the whole interface moves up by about 2 cms/ 1 inch, in order to allow the 'x' button to pop into view. This means that everything moves up by about 2 cms, and everything on the top of the interface get chopped off - including the entire top bar, and the 'closing' button, which totally disappear. It becomes impossible to read any single-line strings that are selected. The only way to get back to the top is to tab into the translation field (the user must TAB, just clicking on the field won't do it).

This is unfortunately reproducible on both Safari and Firefox. Resizing the window makes absolutely no difference to any of the bugs.