If you find SnapNDrag capturing the desktop wallpaper instead of window content, it means SnapNDrag doesn't have the necessary permission.
You will have to make a small change in the Security & Privacy settings to allow SnapNDrag to record the screen.
Step 1: Open System Preferences and click on Security & Privacy
Step 2: Select Screen Recording under the Privacy tab. Click on the Lock icon and enter your Mac account password to unlock. Now make sure the checkbox next to SnapNDrag is checked.
SnapNDrag has an option to automatically import screenshots taken using the macOS keyboard shortcuts (shift-cmd-4). In order for this feature to work, you will need to give SnapNDrag Full Disk Access permission.
Select Full Disk Access under the Privacy tab and make sure the checkbox next to SnapNDrag is checked.
