[Problem to use the color picker with gradient]

Thanks a lot. I did it but in effect it makes no sense to drag this circle. How to do simple when you can do complicated ahhaah. 

Thanks for the help !

[Problem to use the color picker with gradient]

I am trying to use the color picker when I use the gradient tool. It deos not work. 

1) I click on the gradient and I select my first color

2) When I click on the color picker on the top right (nothing happen :-( ) > I should be able to pick a color on my design where I want. It should be the main idea of color picker no?

3) So I decide to open the color selector : again the color picker does not work. Nothing happens

Its soooooo frustated

Did I do something wrong ?