Forcing v-sync in AMD's Radeon Settings eliminates screen tearing in the game for me.
Here are the steps:
1. Open Radeon Settings.
2. Click on Gaming and then Global Settings.
3. Set "Wait for Vertical Refresh" to either "Always On" or "On, unless application specifies" (if you want to be able to turn off v-sync in games that support the option).
4. Turn "OpenGL Triple Buffering" ON. This isn't necessary, but might help, since the game uses OpenGL.
Supposedly, this works with all of the Enhanced Editions of the Infinity Engine games (Baldur's Gate: Enhanced Edition, Icewind Dale: Enhanced Edition, etc.).
If you don't have an AMD card, try forcing v-sync in your own graphics control panel.
On top of your solution I had to check 'Compatibility renderer' on the graphics menu and now the tearing is gone.