Unless you are usingthe Low Level recorder, the coordinates you are seeing are relative to the control being click. In fact, if you remove the coordinates, TC will click the center of the control. All of this means, if the control get moved, TC will find it and click on it.
and how to save the objects to an ObjectRepository? when we open the object browser, what we see is a huge collection of objects which we never require. Can we have a clean and small OR, which contains only those objects which we require?
The 'Object Browser' panel contains all the objects that exist currently in the system, but not the objects you place there. The only thing you can do in order to reduce the number of objects in the Object Browser is to filter the running processes by their name. Please see the 'Process Filter Dialog' help topic for details.