Selecting scale thresholded items
Use Select / Select All to select graphic items before carrying out any edit functions.
Some Items that are scale-thresholded may not always be displayed (for example incidents may be thresholded to display above 10,000 but your current scale may be100,000)
To select scale thresholded items not on display, simply hold down the Alt key and the left mouse button simultaneously and do a drag select.