This type of app really bites us (users) in the ass when we try things real Mac apps have done literally for decades - drag and drop. Drag a file expecting it to be accepted as an upload, but oh wait no, the web view navigated to view that file. And I have no back button so I have to quit the app.
Maybe I miss your meaning but on OS X/chrome: cmd-shift-T to reopen the last window with all tabs. Works even after a chrome restart. Saves me when 40 tabs open and I Cmd-Q for too long instead of Cmd-W.
Yes, I'm aware of this, but it pretty much means the pinned tab behaves like "any other tab". If I closed those 40 tabs, the pinned tab should move elsewhere or persist. Otherwise, I'll have to manually re-pin it all the time.
This is not problem of slack in webview. This is problem of slack. Actually interface in OSX is slower that web view. If you compare optimized Web app and OSX Native app, you will spot difference. Slack is just not optimized.
The recent update is the first one that starts to feel like software to me because the download interface is much less "webby" (and faster for grabbing multiple files from someone.)