In the options for the XMLPlugin, you can set "Pop up tag editor after completion" which will bring up a window in which to edit attributes of the tag that has just been inserted. While the window is useful as such (to see which attributes are allowed for the respective tag), it disrupts the workflow.
Would it be possible to design it as a dockable window? Then you could have it residing silently at one of the docking areas and yet available whenever you need it.
Apart from that, something like "Edit Attributes" or "Edit Tag Attributes" would be a better (=more significant) title for the thingie (but that's just my humble opinion and is secondary compared to the pop-up/docking issue).
(I'm using openSUSE 12.1, jedit version 4.5, XMLPlugin version: 2.8.1, and java 1.6.0_22)