I may do some more focused testing and give more in-depth feedback on āPanelsā another time, but here are my immediate thoughts.
Panels is great in theory. But even after using it for a while I continued to find it a bit jarring to switch my visual focus left and right, back and forth, constantly. I also tend to try to center any info I am most interested in on my screen overall (and I have a 4k, 32" screen), so when the panel would pop-out, it would often obscure or shift some other info I had centered. This latter experience happened most significantly with Docs, anywhere that the primary content was centered, and then a pane would open, the content suddenly shifts to the left and my object of interest is now also to the right. So I think thatās problem #1 with the core mechanic, for me. The utility of side-by-side content and preserved navigation did not outweigh the constant focus shifting.
Second, I feel as though the feature ended up being āover-engineeredā in the hopes to perhaps either A: let people use it exactly as they might want or B: due to being unsure exactly the right behavior in any given situation, and so giving users the option. This resulted in the addition of multiple new buttons and functions (expand/full-screen, collapsed nav history panes on left/right, close panel), and with the simultaneous addition of a Search button on basically all Views (something Iām still unsure about too) and the panel left/right options there, it just became too much I think.
Perhaps it was in part that it is trying to accomplish two things at once, as well: more simultaneous display of info and context preservation in navigation. Either one of those things might have been an improvement, but both together might just have been too big a challenge to make it all work ideally. Thatās certainly a guess though.
Regarding the context preservation, there is a part of me that definitely likes the idea of it, but I think I also find it too obtrusive in the current implementation. As Iāve noted above, consistent content alignment/positioning is for me an important part of feeling comfortable, even āmasterfulā, in my use of a tool. The collapsed panels subtly shift content constantly as you open and collapse them, which I think just subtly wears on me as a low-level micro-adjustment Iām having to now make, all the time. I thin it makes me feel vaguely unsettled.
A possibly better (though probably simpler/less powerful) approach might for example be to adopt the Web Browser back/forward along with the press-and-hold for a āhistoryā list/view (dropdown) to immediately jump back to any previous place. But thenā¦ thatās exactly what the browser already provides. 
Though I imagine many people may not know about itā¦
Another thought that occurs to me is that, although there is definitely exception, in my current work in particular, most often I am opening one thing from e.g. a Table, checking or doing something there, then returning to my table. Being able to reference the table can be helpful sometimes, and 100% there are times when being able to have two entities side-by-side is great. But to have that always be what happensā¦ no, I think thatās going too far. In any case my point I guess is basically that the panel navigation is useful in certain types of work at certain times, so perhaps should be an option somehow (a mode you can switch into, e.g. a toggle somewhere to āsplit content panelā). But in general I donāt want/need it and it just gets in the way a bit.
So those are some scattered thoughts that I hope are helpful. If there are takeaways I think itād be:
- Simplify the model, UI, UX, if possible
- Try to consider panels and context preserving navigation as separate problems
- Prioritize the preservation of content positioning/alignment
- Make panels optional but easily switched into (I have more thoughts/ideas here)
Share Space to Web
When you share a space, everything inside it will be shared (all documents, views, whiteboards, databases with all entities).
Checkboxes and formulas in pinned fields
Improvements
Fixed Bugs