Three related bugs in a horizontally scrolling data table with sticky (frozen) left columns and a sticky right "+" column, plus header popovers: (1) a border-left on a position:sticky cell in a border-collapse table is not visible until the table is scrolled to the end; (2) a closed popover list with a Tailwind `flex` class is rendered open inside the header cell; (3) keyboard focus lands on a header link half hidden under the sticky columns, even with scroll-padding on the scroll container.

Two focus problems with a filter menu built on the HTML popover API in a Next.js App Router app. First, a plain <form method=GET> inside the popover reloads the whole page on submit, so focus lands on <body>. Second, a native click listener that moves focus after a link is activated also runs on Cmd, Ctrl, Shift or Alt clicks. Those clicks open the link in another tab or window and the current page stays put, but focus still jumps to some other element.

A collapsed icon rail that widens on hover and opens per-category flyout submenus (popover="auto") collapses as soon as the mouse moves onto the flyout or leaves, leaving the flyout floating detached; using :focus-within to expand it for keyboard users keeps it stuck open after a mouse click, because hidePopover() returns focus to the invoker button. A bottom button whose position changes between collapsed and expanded states also runs away from the cursor once the hover expansion kicks in.