Why is the an error symol appearing in front of Pinout & Configuration, but vanishing when clicking on GPIO?

[A.D.]

I created a project in CubeMX for a Nucleo board and configured the SPI1 interface.

Now I get this red little error symbol in front of the Pinout and Configuration tab. When I click on GPIO it vanishes (and reappears on any other tab).

Does it have something to do with the GPIO warning

'Warning: Some signals are not used in any IP's mode. However, you can still generate code.'?

I'm totaly not sure what signals Cube is referring to and it does not give any more information...

[eduardo_reis]

I just got the same issue, and I can't figure why that is. I wish there was a tool tip to let me know what is the problem.

BUT, I did close it an opened it again, the symbol was gone.

[koendv]

Just click on "generate code", and a message window will say what is wrong.