Dialog controls use platform specific drawing functions and cannnot be customized (change the color, etc). They often assume specific system colors.
For example, place a dialog list box and a regular list box on your front panel. Now go to your Display control panel in windows and change the color scheme in the appearance tab. You will see that the dialog list box will change the color according to the selected scheme while the regular list box remains the same.
Now use your labview color tool and try to change the color of each. You will be able to change the color of the regular list box, but not of the dialog list box.
Functionally they are the same, the differences are cosmetic.