Please describe the problem:
I was going through a GIMP exercise, using a file called dullsky.jpg, that came with the book I purchased, GIMP for Photographers, and first I ran a tonality correction, which went fine, then I adjusted hue/saturation, which went fine, then when I chose the color picker tool, and chose the sky area, the program would not work correctly when I tried to change tool options. It just wouldn't take anything I tried. Nor could I undo or change tools. It was just in a frozen state. But, in case it's important, when I ran my cursor over the tool options, after some time, I could see the outline of a pop-up window that describes what the option does, but I could not see a text box, which would be the description of the tool. When it happened the first time, I was using 2.2.0, and I upgraded to 2.4, and it happened exactly as it did before.
I did not see if it would reproduce with any other image yet.

Steps to reproduce:
1.run the color picker tool
2. try to adjust tool options
3. 


Actual results:
major-major lag, and the program would not let you adjust tool options, choose another tool, undo, or anything.

Expected results:
freezes up, causes major lag

Does this happen every time?
it did with that particular image

Other information: