Can I prevent Firefox from resizing the date selection control on data entry webpages?

Using an online accounting website, data entry is done through a data grid with a data control. The accounting software allows for the option to use their own date selection control or to use the Firefox date selection control. I don't like the software's date selection control, I prefer Firefox's. However, when set to the Firefox date selection control AND if the fields in the data entry grid get wider than the screen, Firefox shrinks the date selection control to practically nothingness and the value in the control cannot be seen. Is there something I can do stop Firefox from doing this? I've attached an image containing 1. the data entry grid 2. the Firefox date selection control when the data entry grid is wider than the screen 3. the software date selection control when the data entry grid is wider than the screen