tab problem and ties

First, my apologies. I am working my way through the docs while at the same time trying to create a score with tabs.

So, I am asking for help when I am sure the answer must be somewhere in the documentation.

That said, my needs are very simple I want to take this score (posted below) to completion before fully committing to Musescore just to see if it will do what I want it to do... I apologize for that.

So...in measure 10 and 11the half note and dotted half not should be tied but for some reason, I enter the half note in 10 and then the dotted half note in 11 and as soon as I try to tie them the dot disappears and a quarter note is added. It should look something like in measures 2 and 3 but tbh, I don't remember how I got that.

Also in measures 12 and 13 the tablature should be first string fret 5 for the high G's. But somehow I am missing how to correct that.

I apologize for throwing myself on the mercy of the forum but Musescore is a steep learning curve for a 76 year old just learning to play the banjo. I appreciate all the help i can get.