Is this a program or game ?
- If your are trying to find the Compatibility tab on a shortcut for a Steam game the reason there is no Compatibility tab
is because Steam (and I believe some of the other online retailers) use what they call a Web Document as a Desktop shortcut.
It's also possible that a programs shortcut, created directly from the main executable (.exe) has no Compatibility tab, so in either
cases you would want to use the program/games main executable in the program/games install folder, rather than the shortcut.
- With old games this DPI option set to Application will centre the image on the screen properly.
The DPI option - System or System Enhanced can occasionally be helpful when text in a software's Window is too small.