I found a way:
1. Start Stronghold Legends as usual
2. In main menu, click on options
3. In options menu, Click on gameplay
4. Make sure 'Allow quick look' is checked
*To use this feature, during gameplay you need to press down alt while pressing down middle mouse key.
[This message has been edited by taker1 (edited 12-18-2017 @ 06:00 AM).]