I'm often working on information links. To add columns in joins, column elements, filters etc. I always have to scroll through the tables in the data source, open them, add the columns... This is time consuming and annoying work.
My suggestion is to make the search work on tables and columns in the data source itself. At the moment, you can only search for data sources, which is useless in my case, we only have one. You should be able to search for columns and tables with a search syntax like column:xxx, use and/or etc.