Lightroom Tip - Keep the White Balance Tool Active
In the Develop Module pressing 'W' activates the White Balance Tool. You can then move the Eye- dropper over the image to set a white (gray) point.
Once you have set the white
balance the Eye dropper disappears. That is unless you have
un-checked the Auto Dismiss Box on the Toolbar. Note the
Toolbar needs to be active to do this. Press the 'T' key to
toggle the Toolbar.