Does anyone have any idea in BG1 why when installing this mod and talking to npcs, it rolls them into the top left corner? It reverts back once there finished, although I know that it's not meant to do that.
In the original game, the character you speak to is always used to center the screen when you start the dialog, and the game returns to the original display when you leave the dialog. This is the behaviour that you face.
It appears that the Widescreen mod doesn't patch the code where this centering calculation is done, so it still assumes that the display is 640x480. This is what makes the display seem to move to the top-left corner.
To "fix" this normal behaviour, someone needs to find which offset in the executable to patch. This is not easy, unfortunately. It's like the loading screens that are not centered either. This doesn't prevent playing the game though.