Wrong icon and association app The files with extension .tex on my Mac (running Mojave) exhibit some strange behavior:

(a) When I right-click such a file and select "Open With", the first choice is the "TeXshop" app.
(b) However, when I double-click the file, the file opens in the "Texpad" app.
(c) The file icon is a "TeXshop" icon.
(d) The "Get Info" panel, under "Open With..." gives "Texpad".  

Any suggestions on how this can be fixed?
In the "Get Info" panel, the field under "Open with:" should be a picklist, you should be able to click on the list and choose an alternate application. You should then be able to use the "Change All..." button to make that application the default for all .tex documents.