Bookmark folder popups don't show and hide at the correct time

[maxmilton]

On the next branch the logic behind rendering bookmark subfolders has been rewritten.

Before it was CSS based for layout etc. which was great for performance and simplifying logic but had limitations like the inability to scroll a long list of bookmark items or control folder position when overflowing the screen. The new logic is JS based so there's no longer any issues with position and layout, however, the implementation is still incomplete.

Current issues:

• There should be a short delay before opening the first folder on hover to prevent accidental opens (this works now!).
  • After the first folder is open, there should be no delay opening nested folders since that's annoying and feels like the app has frozen (Chrome actually still uses a delay for nested folders but I don't think that's ideal).
• There should also be a delay before closing a folder popup (on mouseout) to closing when the user is moving their mouse to a nested folder etc. (this work now too! Interestingly Chrome keeps folders open until a click outside or ESC key press).
  • The delay timeout speed should be tweaked for the optimal UX.
  • When opening another folder on the same level any existing folder popup on that level should be closed immediately.

Many things here differ from the Chrome UX because Chromium is designed for good a11y however this extension favours speed.

[maxmilton]

Only difference from my original write up is that there's no delay before showing a folder popup. It's not actually that annoying to trigger it by accident and it actually feels very responsive with the immediate open.

[maxmilton]

For my own future reference, the reason we had an open delay before was only on nested folders because it's too easy to open the wrong folder. When moving the mouse between the target folder and its popup, if you happen to mouse over another folder your target folder's popup will be closed.

We'll still need to fix this in future so I created a new issue: #1152