I'm not sure if anyone has posted this yet but I don't feel like digging through posts if it has so here is how you change your auto inventory back to vertical instead of horizontal.
1. Go to your uifiles folder in eq
2. open EQUI_Inventory XML file with notepad
3. Use the find button and search for horizontalfirst
4. you will see a line <HorizontalFirst>true</HorizontalFirst>
5. replace the true with false
6. save
7. reload your skin and back to normal
I just use the default skin not sure if it'll change custom ui's
1. Go to your uifiles folder in eq
2. open EQUI_Inventory XML file with notepad
3. Use the find button and search for horizontalfirst
4. you will see a line <HorizontalFirst>true</HorizontalFirst>
5. replace the true with false
6. save
7. reload your skin and back to normal
I just use the default skin not sure if it'll change custom ui's