T4 Framework using T4 Blank template, Quickstart - Alpha 3 build, Joomla 3.10

A bug was found in the Off Canvas menu.

- Open the Off Canvas menu, then
- click the down arrow next to Pages to expand the second level, then
- click the down arrow next to Layouts to expand the third level.

Instead of the third level opening, the second level closes. Consistently repeatable.

Investigation:
There ARE four third level items to display. The Main Menu module in the off-canvas position is properly set to show all submenu levels ... End Level = All. The issue may be due to the parent item being a page link itself in addition to having subitems and so the right-side hotspot for the down arrow is in conflict with the left-side hotspot to go to the article, but the behavior is to leave the menu displayed and go up a level instead of open the linked article. I suggest the hotspots be allocated 60% left side width to open the listed secong level menu item and 40% right side width to open the submenu associated with the down-arrow.

Also under current UI conventions for accordions, the arrow icon changes to signify whether the sub-item list is open or closed. Currently, it doesn't change. Ideally, it would rotate from pointing right to indicate sub items are available and clicking would expand the list, to pointing down to indicate the sub items are expanded and clicking the arrow would collapse the list back under it's parent item.

I also encourage implementing the suggestion by @mholstein that each menu with subitems recursively slides in an off-canvas style sub-panel over the previous panel. The current accordion approach causes users to lose context due to the sudden change in list length and minimal styling difference and no animation. It also makes some items extend below the fold causing accessibility problems. If staying with accordion, have each level styled differently (apply a higher percentage of bootstrap lighter/darker and font size/lightness so that the information hierarchy remains more obvious. Better is for each sub-menu to recursively slide in just like the top level menu, using whatever is the current off-canvas animation setting. As a demo template, T4Blank should show off the best practice for implementation and the full potential of the framework's off canvas feature.