gradient toolbar, "stops:" dropdown needs a "no stop selected" entry

After creating a gradient by double clicking on a shape or
selecting a shape with a previously created gradient with the gradient tool,
then the gradient toolbar displays the first gradient stop in the
"Stops:" dropdown, even though none of the gradient stops are selected.

In this state, it's not possible to select the first gradient stop from the "Stops:" dropdown list,
another gradient stop needs to be selected from the list, then it's possible to select the first one.

One solution might be to add an entry to the "Stops:" dropdown
that says "Nothing selected" or "no stop selected",
the same way as the "Select:" dropdown shows "Nothing selected", when no object is selected.

Tested with:
r12841 on linux mint 15 cinnamon 32bit