what happened to the blue bar in my Matlab user interface?

One way to start execution of a script is to click on the blue vertical bar to the left of the code. Unfortunately, this bar has recently disappeared from my version of Matlab. This happened while I was using 2023a and there is still no blue bar even after I upgraded to 2023b. I am using a Mac. Can you help me figure out how to get the blue bar to reappear?

[Dyuman Joshi]

"One way to start execution of a script is to click on the blue vertical bar to the left of the code."

That's weird, I've never heard about this nor have I seen such bar in any of the MATLAB versions I have used.

Do you have a screenshot of the UI featuring that bar which you can share?

[Voss]

@Dyuman Joshi: I had also not heard of or noticed this, but apparently it appears in the editor with a script open, when hovering over the area to the left of the line numbers. Screen shot from R2022a:

[Walter Roberson]

I never noticed that before, but the blue bar is present for me on R2023b Mac Intel

[Voss]

@Richard Goldberg: Are you sure you have a script open in the editor? The blue bar does not appear if you are editing a function.

[Cris LaPierre]

It is always visible in Live Scripts, but also visible in m-files if you hover your cursor over the space to the left of the line numbers.

[Richard Goldberg]

Here is a screenshot from my Mac with no blue bar:

And here is the same file on a Windows machine, with a blue bar along the left edge:

[Dyuman Joshi]

@Cris LaPierre, I found the bar in the live script editor, but couldn't find it in .m files. (R2021a Win 10)

@Richard Goldberg, you can also run the code in live editor by pressing CTRL and ENTER together.

[Cris LaPierre]

Looks like it was introduced to m-files in R2021b

[Dyuman Joshi]

Yes, you are right - https://in.mathworks.com/help/matlab/matlab_prog/create-and-run-sections.html

Answer 1

[Richard Goldberg]

OK, problem solved! I followed the instructions here to regenerate my preferences: https://www.mathworks.com/matlabcentral/answers/99625-how-do-i-regenerate-my-matlab-preferences

For step 2, it's important to create an empty folder with the original name, so that Matlab generates a new set of preferances instead of copying the preferences from another version. I forgot to do that the first time and it didn't work, but did it properly the second time and it was successful!

Answer 2

[Image Analyst]

The blue margin indicates the extent of the section you are in, meaning that the blue bar runs from the starting line of the section until the last line of the section. If you don't have any sections (started by a double %) then you should have the blue bar since it's all one section. If you have two sections it will appear if you're cursor is in the section and the section is displayed and you hover the mouse over the margin. If the current section is scrolled off the screen, then hovering over the margin will not show blue because the section is not in the viewport. If you click in the viewport, now the current section and displayed section are both visible and you will get a blue margin upon hovering the mouse.

[Richard Goldberg]

Yes, I completely agree with what you write above. But as you can see from my screenshots above, something has happened to my Matlab settings on my Mac to cause the blue bar to disappear. It used to be there but now it's gone. And when I open the same file on a different computer, it is there. I can't find any settings that would affect this, and I'm wondering if there is some settings file buried in the installation that I can change or delete to fix it.