No editing area has a caret on Linux in the 1/28 build. I thought I saw one there in 1/27, but maybe it was 1/26 (several other Linux users have indicated that they saw this bug starting on 1/27). Saari says he'll do some preliminary investigation.
I just tested, and this isn't my fault, focus is fine. I see DrawCaret getting called, and since it is only not drawing on linux, I'm going to venture a guess that this is Pav's fault.
i fixed this
verified in 2/1 build.