have to click twice to choose an entry into a drop-down list

Hello,

I have this issue and it doesn't seems to be related to to default browser as I get same issue under firefox and internet explorer.

When I have a drop down list, the first time you click on it, it's expanding but if you chose an entry, the entry stays blank. Then, you have to click a second time for it to work.

And it's not always the case.

It seems that it is only working if I'm first browsing into the list, and making a selection then. But if I open it directly and want to choose the first entry, it doesn't take the value.

Could someone please help?

Thanks!