Filter the projects in the repository browser to see only the one(s) that you want to work with. The Project filter field is on the toolbar. Enter the name of the project you want to see in the Project filter and all other project will be hidden. The filter string is saved when closing and reopening the workspace. To clear the filter, delete the text in the input box and press Enter.
Use wildcards and regular expressions to refine the project filtering.
If you have 5 projects named Project 1 through Project 5 and enter Project [1-3] in the project filter, only Project 1, Project 2, and Project 3 will be shown in the browser. If no projects match the filter, the Browser will be empty.