mouse keyboard conflict

Ever since I upgraded to Sierra (currently upgraded to 10.12.6 on new MacMini) my mouse is acting up. If I touch the keyboard (new apple keyboard) when trying to click on something with the mouse it does strange things to the text. When I have a whole page of text highlighted in a document I have to click the page several times in several different places to get it to release the highlight. In some documents, like using BBedit, when opening files, it won't let me double click to open files and I have to choose "open" instead. There are several other problems I forgot to write down. I"m using a Logitech mouse. Can anyone tell me what might be wrong?