Check this video after the 20th second. You will notice a new bug there. When I collapse a floating toolbar and then I expand it again, it loses the ability to show the mouse tooltips.
The only way to fix that is to entirely close the toolbar and then open it again. No big deal for me personally, but it’s still something that could be improved in the future. Especially for novice users who still try to learn the icons.
the collapsing toolbars is an unintended side effect of the collapsing panels. If you think collapsing toolbars is useful let me know, but it seems a bit silly to me, since it keeps showing part of the tools.
I think it doesn’t properly rebuild the toolbar after a collapse. If you have two toolbars in that container and collapse, then switch to the other tab you’ll notice it glitches even more, and the toolbar buttons will be invisible.
This is a highly useful feature and I believe that your decision to leave it this way is great, because the user is not forced to close the floating toolbars entirely, but is still able to save a lot of space in the viewport by collapsing them for a while until they are needed again. I hope that this feature could be expanded further by enabling the mouse tooltips after a prior collapsing.
As I mentioned, I have no trouble with the lost ability for showing the tooltips, because I’m used to the icons. However, I made a tutorial in the video above and I was unable to show what I press for the viewers.
Sometimes this bug still appears. I found that it happens randomly when I access a sub-toolbar of a secondary toolbar, such like when I want to access the ! _FilletSrfCrv tool (Main toolbar > Surface tools > Surface fillets) or the ! _Intersect tool (Main toolbar > Curve tools > Curve from object). If I drag the sub-toolbar to make it a floating window, sometimes it tooltips refuse to show.
What’s interesting is that if I hover the mouse pointer over the faulty floating window, and then I move the mouse pointer over another toolbar (like the top main toolbar consisting multiple tabs), the latter also gets “infected” and refuses to show mouse tooltips. However, if I move the mouse pointer over the Main toolbar on the left side, it “cures” the tooltips of the top toolbar and it’s able to show tooltips again.
However! If I move the mouse pointer on the faulty floating window again, and then go back on to the top toolbar, its mouse tooltips stop working again. If I repeat the process and hover over any icon on the Main toolbar on the left side, it “cures” the top toolbar again. Weird…
I also noticed that some of the floating toolbas that were left opened when I closed the Rhino 9 BETA, also can’t render the mouse tooltips sometimes. I’m forced to close the floating toolbars and then open them again, in order to force Rhino to show the mouse tooltips.
After installing the awesome plug-in byRhinoGadjet from Package manager, the tooltips of the Main toolbar on the left no longer work. They don’t work even when I restart the latest BETA. Weird.
I don’t think that this particular plug-in causes the bug, because the tooltips don’t work most of the days for a random reason anyway.
Every day I learn things about Rhino. I had no idea you could click the tab and it temporarily goes to one line, neato!
The fact that tooltips suddenly stop working due to this is very odd though. I cannot reproduce this but I’ll YT it so it’s on my pile.
YT : RH-99290 Mouse Tooltips may not show
I believe that @Gijs did that wonderful functionality about a month or two ago after I asked for a toggle to minimize the UI of the floating panels of the Analysis tools. It’s a real game changer as it releases a lot of free space in the viewport.
Regular toolbars also collapse to a certain extent, though they could be further developed to utilize the functionality slightly better.
I like it, it’s very nifty! I shall be using it 
I just installed the latest BETA, yet the mouse tooltips are still inconsistent. I noticed that when I move the mouse pointer from one toolbar to another faster, there is a higher chance to trigger the bug that prevents the tooltips from showing upon mouse hovering. However, when I move the mouse pointer slower from toolbar to toolbar, the bug happens once in a while.
Another observation is that when I move the mouse pointer from one toolbar to another, and the first icon refuses to trigger the tooltips, I can still fix that by moving the mouse pointer over to the next icon. That seems to “awake” Rhino and “remind it” that it should activate the mouse tooltips. If I move the mouse pointer to the first icon that didn’t trigger the mouse tooltips, now they show up properly.
Here is a video of the aforementioned testing process:
