Problem description: when the color-picker dialog is opened in the Graph widget configuration form, the chosen color is not shown in the input element in the top left corner of the dialog.

Steps to reproduce:

1. Open any dashboard and press Add widget button
2. In the opened widget configuration dialog set Type = Graph
3. Press "Add new data set" button
4. Click on the "Base color" of any of the two data sets
5. Check the color in the input element

Result:
"Undefined" color is shown
Expected:
The current color of the data set should be shown

Example: