How can I force PyCharm to inspect the requirements.txt file and suggest updates?

I tried opening any .py file, checking Package requirements file field (Settings - Tools - Python Integrated Tools). Nothing triggered my PyCharm on Windows to detect a new dependency added to requirements.txt. Since the virtual environment was created with PyCharm's Add Local, trying to get pip to work for the virtual environment with a Windows command line also seemed quite a bit of work.

Finally, the easiest solution that worked for me was as follows.

1. Click on the icon in the lower left corner. It brings up menus to Project, Python Console, Structure, TODO, etc. Find Terminal in it.

   

2. Click on Terminal. It seems to be automatically virtual environment aware.

3. Run pip install -r requirements.txt

Open any .py file after requirements.txt has been changed, PyCharm will parse requirements.txt and suggest updates, e.g. packages installation.