Enable IDEs Auto "Merge All Project Windows" for macOS

Question

When working on macOS with JetBrains IDEs, after opening a project, you have to invoke the menu Window | Merge All Project Windows to merge the project to the IDE's project tab. How to do this automatically?

Answer

There is a feature request about this: https://youtrack.jetbrains.com/issue/IJPL-59820/Enable-Auto-Merge-All-Project-Windows-for-macOS, currently please use this workaround:

macOS System Settings(not in IDE's Settings Page) -> Desktop & Docks -> Windows(scroll down a bit) -> setting Prefer tabs when opening documents to Always.

It's a macOS Big Sur and higher version feature, and the IDE now respects it.

Changes Prefer tabs when opening documents to Never will always open the project in a new window.