Word completion plugin focus and keymap

[ggustaf]

 * Xed version:  2.4.2 and 3.2.7
 * Distribution:  Mint 19.3, 20.1

Issue
The word completion plugin offers one or more words to choose from. The select key is RETURN.
When typing text, a RETURN ends the current line, so RETURN will be pressed many
times during editing. The FOCUS on the popup is set by the plugin to the popup highlighted word, which causes a RETURN to choose the highlighted word in the popup, a conflict with normal editing.

If the FOCUS is a bug, then the FOCUS should be fixed. If the select key for the Word Completion window is configurable, i.e., change RETURN to TAB in settings, then that would resolve the issue.

At present, documentation for Xed says nothing about configuration of the plugin. A message is printed in Preferences about Ctrl-SPACE. That key appears to do nothing.

Steps to reproduce
Enable the plugin.
Open a NEW document.
Type in the words "printable, printed, printing".
Type a line with word "print", stopping at the end of the word.
The Word Completion popup will offer "printable" among other possibilities.
Hit RETURN after "print". The popup chooses "printable", then
the popup-altered comment line has to be edited.

Expected behaviour
The plugin popup highlighted line (the popup focus) should be selected and copied into the text only for a special key. The text cursor focus should remain in the main text, not in the popup.

Other information