Found the problem that was causing the coordinate modification: by changing one coordinate the four vertexes of the rectangle are not coplanar. Modified the data structure and the rectangle driver to work only with three coordinates and generate the fourth but still doesn't update on the screen the modification. Made a C++ simple test application to verify the algorithm and that works properly.
Will continue researching on this problem.
Installed AlibreDesignExpress and looked at the GUI layout. It seems that they don't use a property dialog, the main dialog is a tree list with the objects displayed. I will have also to consider creating a mechanism that displays to the user some object properties using the data from the data tree. Ex: In the data tree the coordinates are stored but to the user it is displayed the rectangle width and height, when the user changes these in the data tree the coordinates are updated, there is no need to display to the user the coordinates. This also should consider the fact that more complex properties can't be displayed on a grid, a dialog would be more appropriate.