VS Code: Search multiple directories

Did you try a comma like ./dir1, ./dir2? For me it seems to work

By the way, here is the documentation of 'files to include': https://code.visualstudio.com/Docs/editor/codebasics#_advanced-search-options

In particular, you can use glob notation. Also, VS Code will include/exclude certain directories or files by default, depending on your settings.json, in case anyone still sees unexpected behaviour.