Returns true if the control is marked as display only, otherwise returns false. This method only returns true if
this specific control has been marked as display only, and does not check if the control is display only because one of its parents has been
marked as display only. Use method #isDisplayOnlyIncludingParents() to check whether the control will be displayed on the page as display only.
trueif the control is marked as display only, otherwise returnsfalse. This method only returns true if this specific control has been marked as display only, and does not check if the control is display only because one of its parents has been marked as display only. Use method #isDisplayOnlyIncludingParents() to check whether the control will be displayed on the page as display only.