There was no error, when you select the Range tool it immediately applies its previous setting, if any, but the sliders are still active so you can go ahead and select a different range if you want. This is consistent with how other tools such as the Blur tool work -- when you select the Blur tool, it immediately blurs the mask, but you can change the setting by adjusting the slider. If you want to quickly reset the Range tool you can use the Contract button.
There was no error, the program just did not behave the way you expected.
When you select the Range tool, the previous settings, if any, are restored and the tool is applied. If you don't want the previous settings you can just move the sliders or press the Contract button to reduce the range to a single color and the shift drag over the input image to expand the range from there. This is consistent with the way, for example, the Blur tool works -- you select the tool and it immediately blurs, but you can move the slider to vary the result.
Sorry for the double reply -- did not notice the discussion spilled over onto a second page.
I think what he was suggesting is that you start with the image you want to process, then add a splitter after it. In one branch you use Masks and set its output to the combined mask1 + mask2 as discussed earlier by creating the 2 masks as mask 1 and mask 2 within a single Masks transformation and then use its Settings menu to set the output image to mask 1 + mask 2.
Then, in the other branch you reference the combined mask in whatever transformation you want to use it with (by selecting it from the Amount mask dropdown menu. The Copy method also works fine, but the splitter keeps everything on a single branch so it is more obvious what each transformation depends on.
I am not sure if what you are trying to create is a mask that is white where either mask 1 or mask 2 is white or where both mask 1 and mask 2 are white. Looking at your example, the easy way to do this is to create mask 1 and (without closing the Mask dialog box) then select the linear gradient mask tool and create mask 2 (the gradient mask) with the mode set to Add or Overlap depending on whether you want mask 1 or mask 2 vs mask 1 and mask2. From the example it looks like you want the latter. Using this method you don't need a splitter or a Copy as you can do everything within a single mask.
