View form in modal/sam window

I have some grids, and linked each of them to their forms. I originally set them to Link Operation Mode : open in the same window, but then changed them to modal.
But somehow, I don’t know what went wrong, the setting changed back to open in the same window.
When I run the grid, and click on the form buttons(add new), the form is displayed in the same window. I click exit, go back to grid, and click the form button again, the window now suddenly displayed in modal???

Seriously, I need help in this. I’m kind of getting tired of seeing some anomalies here.

Thanks in advance.