Which tool are you talking about?
Try resetting the preference of Editor and see if that solves your problem:
- Close Elements.
- Launch the Photoshop Elements Welcome Screen and hold down ctrl + alt + shift as you click Editor.
- Continue to hold the keys until you see a message box asking if you want to delete Photoshop Elements settings file; click Yes. Elements will open with default preferences.
I believe you are talking about "make dull sky blue" in quick edit. It can only enhance the color in the section of the image having the sky. It can not convert gray sky to blue. You can look for a few methods to replace your gray sky to a blue one.