Unable to drag and drop any files

Scenario : You click on a file and try to drag it to drop it into an application but you are unable to do so. Try as much as you may, you are not able to drag it. What do you do ??

Solution : You tried to drag a file into an application but it just does not allow you to do so. You try to drag a window, it does not allow you to do so too. You can click and select the file, you can also resize the window but you cannot drag anything. What do you do ??