Close currently open server browser filter before opening a new filter added with "New filter". Otherwise two filters would be open at the same time, which is not intended and causes the scrollbar handle to become very small.
Using just two server filters with default settings ("All"), i.e. filters including all servers, causes significant lag spikes when refreshing the server list (including when initially starting the game).
This is caused by the following code (in particular the std::stable_sort), as the entire list is resorted for every server entry being added to a filtered list:
https://github.com/teeworlds/teeworlds/blob/6b7fa9308e59ac8110f2aa58a03bdd50995c0266/src/engine/client/serverbrowser_filter...
