When the current tab is the last one in the tab strip, opening links in background tabs from that tab gives almost no visual feedback that new tabs were actually created.

In the standard tab layout (with or without Mini toolbar enabled), if the active tab is the rightmost one and I Cmd+Click a link (or use “Open Link in New Tab”), the current tab stays visually “glued” to the right edge of the tab bar. The tab strip does not scroll, and the new background tabs open somewhere to the right, off-screen.

Because nothing moves and there’s no visible indicator, it looks like the click didn’t register at all. I often end up Cmd+Click-ing the same link multiple times and later discover several identical tabs opened in the background.

Use the standard tab layout (View → Tabs → Standard), with Mini toolbar either enabled or disabled (bug reproduces in both cases).
Open enough tabs so that the tab bar becomes scrollable horizontally.
Scroll all the way to the right so the last tab in the strip is active and visually touching the right edge.
On that page, Cmd+Click a link (or middle-click / context menu “Open Link in New Tab”).
Observe the tab bar.

Actual result

The active tab remains visually fixed to the right edge of the tab strip.
Newly opened background tabs appear to the right but are off-screen.
The tab strip does not auto-scroll, and there is no other visual indication that tabs were created.
This makes it easy to unknowingly open multiple duplicate tabs.
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Expected result

When opening background tabs from the rightmost visible tab, there should always be a clear, visible reaction in the tab strip.
If there is still horizontal space to keep the current tab fully visible, Orion should slightly shift the tab strip to the left so that at least the leading edge of the first newly opened background tab becomes visible, without making it active.
If there is enough room, the newly opened background tab should be shown fully, pushing existing tabs to the left, but only up to the point where the current tab would start leaving the visible area — the current tab should remain fully on-screen.
Once the current tab reaches that “last possible” rightmost position (any further shift would move it off-screen), additional background tabs should still trigger a subtle animation or “peek” at the right edge of the tab strip (e.g. a small shift, pulse, or partial reveal) to indicate that new tabs have appeared off-screen.

Version 1.0.0 (139), WebKit 623.1.8.0.0

Tahoe (26)