When adding new Spotfire Controls on Text Areas I have to be very careful not to loose my control. Even with years of experience using Spotfire, I have to make sure the element is not highlighted when adding new ones. To do so, I have to click out of it to unselect any other component before adding a new control. Otherwise I loose my control because it will be replaced with the new one.
Ideas to reduce confusion:
1) Add a warning dialog (as per the attached animation)
2) Keep the selection of the control highlighted in blue (not gray) when the control looses its focus