The bathtub drain stopper that is located in the tub 3/4 of the way up to the top of the tub does not stay down. The lever pops back up by itself when pushed down to open drain and therefore, the tub fills with water when the shower is on. How can I fix it?

Hi Flash:

You'll want to go and purchase a replacement trip lever face plate... see image. Most of these are universal fit.

Here, you'll unscrew the old screws to remove the old trip lever assembly and then remove the cotter pin on the back of the trip lever face plate and swap out for the new face plate. Install the new chrome screws and you should be all set here. A new cotter pin and chrome screws should come with the new face plate

Any questions... let me know.

Mark