My model is relatively small (26Mb) but it is taking 2-3 seconds to enter each group, which adds up considerably when having groups within groups. I performed an extensive cleanup of the model through purging, deleting unused components and materials, deleting section planes, deleting unused layers, but the lagging when clicking into groups has not changed. The solution we have found is that when we open a new instance of SketchUp, and duplicate everything in the model to the new one, this fixes the issue and now it takes a split second to enter groups easily. While this solution works, we lose all of our dozens of scenes from the previous model, and creating and copying over all of those cameras would just take too long.
What I am wondering is, both of these models are the exact same file size (26Mb), but one lags considerably when entering groups and the other has no issue. It seems the issue is beyond a large file size, but something else. Any ideas?