This program works through window hooking. Hooking is a technique that Microsoft suggest you only use in debugging because it can slow the system down, and interfere with any other program on your system (or even crash them!). So use at your own risk.
When allSnap is closed in the middle of its uninstall, or in certain other situations, the library file (snap_libA.dll or snap_libW.dll) is not released correctly. This makes the uninstaller unable to delete the dll. If this occurs, restart the computer and delete the file and directory manually.
Here is an incomplete list of windows allSnap cannot affect:
This may cause the strange effect of windows that can be snapped to but not snap themselves.