i have this strange behaviour when i have grids in my forms

if any of the grids is populated such that i have to use the scroll bar (on the grid) the form gets stuck and the only way i can continue is if
i double click on the title bar

if the grid has just one or two lines populated (or if the grid is populated such that i dont need to use the scroll bar) then there is no
problem

i have no commands or controls on the grid, nothing whatsoever

any body can figure this out