In ArcMap, you can collapse folders/gdbs/datasets by clicking the back arrow anywhere within the folder/gdb/dataset. For example, if a feature class within a dataset is highlighted, the first time clicking the back arrow will make the highlight jump to the feature dataset. The second time collapses the dataset, the third time it jumps to the gdb, the fourth time collapses the gdb, then it jumps to the folder. It always jumps to the folder/gdb/dataset above and, when the back arrow is pressed again, collapses it. This way, you can collapse and open the entire catalog with just the back and forward arrows. This helps navigating the catalog easily.
In ArcGIS Pro, opening folders/gdbs/datasets by using the forward arrow works. However, collapsing a folder/gdb/dataset only works when the folder/gdb/dataset is already highlighted. If you have a dataset with a lot of feature classes and the one at the bottom is highlighted, you first have to navigate all the way to the top to reach the dataset in order to collapse it.
