toolbar icons disappear when switching from light to dark mode (restarting Npp or switching back to light mode fixes problem)

[molsonkiko]

See the issue title for a complete description of the issue.

Before switching to dark mode:

After switching to dark mode:

[molsonkiko]

I can no longer replicate this bug on a build of the current master of Notepad++ (between 8.6.4 and 8.6.5), so I believe this bug will be resolved in Notepad++ 8.6.5 (which is not yet released).

Well, I thought it was fixed in Notepad++ 8.6.5, but I guess not?

Note that JsonTools older than v7.1 have numerous problems on Notepad++ 8.6.5, so this is yet another reason to upgrade to v7.1.