In Illustrator CS6, I can only get the gradient tool to add a horizontal gradient.
I can not drag either of the end points around into a vertical gradient.
What is going on here that I can't see?
With linear gradients, you can not drag the gradient annotator around to various angles. It will remain at the angle it has been set to.
If you want to drag an angle, use the Gradient Tool and click where you want the gradient to start then drag to where you want the gradient to end. You can click-drag any angle you need.
Alternatively, you can use the Angle field located on the Gradient Panel to set the angle of the gradient.
It is only with radial gradients that the annotator will rotate around it's center, never with linear gradients.
Had the same exact problem. Make sure that your fill is selected and not the stroke. This was my issue. Hope this helps!