@Okie, now I see what you were talking about in the other thread. I think you did not do a good job explaining, because most people have never been in that situation. Experience informs a lot of our knowledge. Both you and @wrosie are good people - both of you are smart and often have solid thoughts. Pardon me while I explain a little about this. Then, let's hug this out. The Doc and I have to do this all the time, though we might do more than hug.
I was born, raised, and a residence of Virginia. When I went away to college, it was in North Carolina. When I was at school, for 9 months out of the year, I worked for the State of North Carolina. When I was home for the summer, I worked a small job here in Virginia. Because I had income from two different states, I had income tax withheld by both states and I had to file income taxes for both.
Years later, I lived several years in Oklahoma where I worked at the time. Late during the 3rd year there, I moved to another state where I had gained employment. At tax time, I filed taxes for Oklahoma and the new state. Had I moved to a third state and worked in that state in that same tax year, I would have filed 3 different state income tax returns, if the 3rd state had state income taxes.
Another situation that often arises here where I live now, which is on a state border, is that many people live in my state, but work in the state that is one mile from my house. Assuming their only job is in that other state, they would only file taxes for that state, though their residency is here.
In Okie's example, if a resident of Wichita Falls, TX worked across the Red River at the Comanche War Pony Casino, which is on the other side of the Red River into Oklahoma, that person would pay state income tax to Oklahoma and file their state income taxes with Oklahoma, though they are a legal resident of Texas and would not be subject to state income taxes if they were working at the Buns Over Texas Bar & Grille in Wichita Falls instead.
There are other reasons why a person might have to pay state income tax to a non-resident state, but I won't go into that here. I just wanted to explain and provide a couple of examples. Now, let's hug!