Sublime Text 3 shows no files in your sidebar

A few days ago I installed a new interface and syntax theme for Sublime Text 3. Yesterday I wanted to post a new link to my blog and switched from the beyond tellerrand project to my personal blog. What was this? I did not see any files in the sidebar. I switched back and also all the files in the beyond tellerrand projects where not shown.

Of course I thought it was the theme which caused this. I pinged the creator of the theme, but he was quite sure it was not his theme. In parallel I did a search and found out, that ST3 has this issue, when you turn on “Show Open Files” for one project and not for another, the files disappear for all your projects.

Solution, as shown in the little video below, is to either turn on or turn off this function for all projects. You have to restart Sublime Text and all files are visible again. Use View > Side Bar > Show Open Files to activate it.