After editing the part, look at the characteristics of the toolbar. There is an "assembly transparency" in it. Just adjust the transparency. Here are other methods:

1. Take a simple assembly as an example. Open the assembly, you can see a cuboid, but you can't see the cylinder of another part, and the part is not hidden. So, where did the cylinder go? The answer is in the cylinder part drawing.

2. We click to open the cylinder part drawing, and then we find that there is no cylinder in the part drawing.

3. Look at the cylindrical feature in the status bar on the left, right-click the feature and find a small icon of glasses. At this time, you will find that the label of the small icon is displayed, that is, the feature is hidden.

4. Click Show and the cylinder will appear.

When you go back to assembly, you will find that the parts are back.