This is my #1 complaint with optimized forms. It is not obvious at all that they are supposed to click in that text to choose their designation. You can set up a dummy fund and call it something like Click Here to Choose Designation and set that as the default fund, but then that eats into your already limited number of funds that you can have in the selector, if someone misses it, then you have a gift to a dummy fund and finally, having a dummy fund is just bad data management.

I believe there is another idea that is similar to this one. It it NOT obvious to the donor what they need to click on to select the specific fund they wish to donate to. It was not obvious to me the first time I set up/looked at the optimized donations forms. When I have shown the forms to others in our org, they always ask how the donor selects from a list of funds. It need to be more obvious to the donor how to do this.