How to change the file veiwer GUI setting to show all file types by default? Also, how to select multiple files at once?

When I open the file locator to open a saved work space or import some data, using the GUI not a script, the default setting is to show only files associated with Matlab. Is there a way to change this so that by default it shows all files types?

I import lots of data with different files types like .txt or files with no association, and it is a hassle that you need to import one file at a time, thus I would like to be able to import more than one file at a time without the need to write a script.

Are either of these two problems solvable?