I find the "new and improved" Editor UI in R2021b to be extremely irritating, in no way better than R2021a. How did this get past SQA? Following is a list of miscellaneous nuisances that I've run into:
The text search/replace box obscures the top text line in my file, which is a problem if the search text is obscured.
It isn't obvious how to revert to previous search strings in the search box.
I want to rename a variable in my m-file, and before doing so I want to ensure that the new name, "num_subset", does not already exist in the file. However, there are many occurrences of the substring "num" in my file, and as soon as I start typing in the search box it jumps to the next occurrence of "num" before I've finished typing. So now I have to go back and find the place where I was working.
In an auto-indented code section such as a while ... end block, if you insert more than one consecutive blank line in the code the auto-indenting is lost on all but one of the blank lines.
In an auto-indented block of code, if you put the cursor between two characters and press ENTER, the Editor will put in a line break with the new line indented, as expected. However, if you select (click-and-drag over) a character and press ENTER, the Editor will delete the character and replace it with a line break, as expected, but the new line will not be auto-indented.
After doing a text search you can do subsequent searches for the same text string using F3 without re-opening the search box. However, if you switch to another file (in the tabbed Editor window) F3 does not work; you have to re-open the search box. It worked in R2021a.
The search always wraps, but I usually don't want it to wrap. There appears to be no way to disable wrapping. In R2020a the search box had an option for enabling/disabling wrapping.
The behavior of Smart Indent has changed in 2020b. In 2020a all lines in a code block would be auto-indented. In 2020b the indenting of all blank lines is removed. So if you start typing in a blank line you have to either manually put in leading tabs or re-select Smart Indent.