I recently updated to 2021.2 and just noticed this problem, but I'm unsure if I accidentally changed a setting or if it's a platform change.
Previously, I was able to click "Show Diff" in the Git panel and it'd pop-out a lightweight diff viewer. This is great because I could expand it however large I needed.
Problem: Now when I click "Show Diff", it opens the diff as a new tab in the editor. Combined with the real estate that the diff tool is using, this leaves very little room to review the changes. It also makes for a confusing view in the main editor, since the diff tab is seemingly randomly thrown somewhere in the middle of my open tabs.
I found that if I changed the "View Mode" from "Dock Pinned" to "Window", then the diff viewer behaves like I want -- but now anytime I click the Git panel, it opens the new window, which is not what I want. I like to be able to quickly reference the list of changed files in the panel (without a new window).
The "Show Diff in new tab" doesn't seem to do anything different, I'm not sure what it's supposed to do, but both options open a new editor tab with the same view.
Is this new behavior, or is there a setting I messed up somewhere? Thanks in advance.