Improvements:
- Fixes autocomplete text remaining in field after selection in Fx60
- No more text or icon shifting on select (tested on macOS)
Changes:
- Tags are now selected on mousedown with no active state, as in web
library
Regressions:
- Tooltip with tag type doesn't appear when hovering over icon
- Pressing Tab after modifying a tag loses focus
- Right-click in textbox shows custom menu instead of default text
editing context menu (Cut/Copy/Paste)
To-do:
- Switch to this version for note tags box
- Style colored tags in autocomplete drop-down? Sort to top?
- Only show delete button on row hover, as in web library?
- The Mozilla CommonJS loader is no longer available, so bundle the
Fx52 version of it
- Strict mode is enforced
- `this` is only defined as a global object in .jsm files, not .js files
- `this` can't be converted to a string for BackstagePass test, so check
for presence of Components.utils.import instead
- The return value from import() is no longer available
