This is not a feature I use often so my problem is probably due to lack of experience.
I have a model with a number of components. Some of them have the option to `Replace with Selected greyed out. It doesn’t matter whether I select items first or not.
I already have components of one steel post in the drawing and have created a new one to replace it. As there are a number of them, using this facility would be handy. But mainly I want to understand why SU thinks some of the components are not suitable for replacement.
If those components are nested in other groups or components you would need to open the parent component/group for editing. The Select Instances only works for the current context. And of course Replace Selected only works if the components are different.
Here is a screenshot.
I have opened a group that contains all the steel members. But still when I look at the 150 x 90 component, it is greyed out. So I am not convinced nesting is the problem.
So you’re selecting the 150 x 90 PFC in the model and then right clicking on that component in the Components browser. The reason Replace Selected is grayed out is because there’s nothing to replace. They are already that component.