public boolean isInsertAllowed(DataType dataType) {
		int rowIndex = getMinIndexSelected();
		if (rowIndex == -1) {
			return false;
		}
		return isInsertAllowed(rowIndex, dataType);
	}
This adjusts the selection so the blank last line cannot be selected
if any components are selected.
In no components are selected, this will select the blank last line.
@return true if the selection was changed.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/compositeeditor/CompEditorModel.java