Hi there! I am having an issue with this. I have placed subassemblies into my final assembly with aim to be able to move the components. However it seems that all components are defined. I have check with the mates, its ok. Also @ the solve as rigid/flexbile check box, its disabled and I am not sure if I need to check it, but the issue is its disabled and i couldnt do anything with that box.
looking at your image, then you can have that part flexible - it's a part. only way to have it 'moving' is to either model it with reference to other moving components or add configurations with different positions of it.,
Make Flexible - is for assemblies