Searching via keywords requires you to right-click on a keyword, click "Find" to bring up a different window, and then click "Find" again. This is not very intuitive and the UX isn't very good. In the Keywords panel, you should be able to click the Keywords you want to search for and then click search. I don't know if this requires a new panel just for searching or if there can be two buttons at the button of the existing panel: "Add" and "Search" (or "Find") - one for adding keywords to a file and one for searching by selected keywords.

Also, currently, when adding more Keywords to the Search / Find criteria in the Find Pop-up window, you have to type them out, which could lead to misspellings or forgetfulness. There should be a dropdown of all the current keywords to choose from instead.