Not possible to toggle with arrow keys before having finalized japanese input

[MickMonaghan]

Env
Windows 10
Chrome v51
Japanese MS IME
CodeMirror: v5.13.2 (also exists in v5.16 - and earlier versions)

To reproduce:

• Open a code mirror mirror input area
• activate the Japanese IME
• Enter e.g 'nippo' in Hiragana (Microsoft IME)
• Press space once
• use the left arrow

Expected Result

• Cursor moves. This works in MS Word, Notepad etc

Actual Result:

• The left arrow key does not move the cursor

[marijnh]

This is a case much like #4095 -- CodeMirror is trying to show an interface similar to that the IME module might be showing, but it doesn't have enough information to do a very good job there. Switching to inputMode: "contentEditable" does help here, since that allows the user to see the native interface.

If having some indicator of where the current selection is is important, it seems that I could periodically read the cursor position from the textarea, and show CodeMirror's cursor at the matching position, during IME. However, this still does not tell the user what group is being worked with -- I had hoped that the current group would be selected, but the only thing that happens is that the cursor is put in front of it, and I don't think there's a workable way to find out how the composed text is split into groups.

[marijnh]

(Note that the arrow keys do seem to work, you just don't get visual feedback on their effect.)

[hungys]

Same issue on Chinese IME (Bopomofo)

I initially reported this issue on Ghost's repo (TryGhost/Ghost#9012) but it seemed to be CodeMirror's issue.

[adrianheine]

This is a issue that is difficult if not impossible to solve with the fundamental approach currently taken by CodeMirror.

We are working on a rewrite (CodeMirror 6) that will address this issue, and we are currently raising money for this work: See the announcement for more information about the rewrite and a demo.

Note that CodeMirror 6 is by no means stable or usable in production, yet. It is highly unlikely that we pick up this issue for CodeMirror 5, though.