When you select multiple elements, it can be difficult to determine whether you have selected the intended elements.
To verify this and make any needed adjustments, do the following:
Revit LT indicates the total number of selected elements using:
The Filter dialog lists the categories of the selected elements. It also indicates the number of selected elements in each category, and the total number of selected elements. You can clear check boxes to deselect categories of elements. See Selecting Elements Using a Filter.