VS 2017, WPF
I have a WPF project in which several self made User Controls are defined. On a window, I have added these controls directly on the window grid as well as on grids on tab items of a tab control.
The project compiles and runs fine. There are no errors in the XAML view or designer view of the User Controls. There are no errors in the XAML view of the window.
Here is my problem: in the designer view of the window, all my User Controls get the yellow triangle warning sign. How can I find out what these warnings mean and why they are there ?