Ah, sorry, I missed a step! The Properties window shows the properties for
whatever is currently selected, which might be the report itself, one of the
sections of the report (Detail, Report Header or Footer, etc) or one of the
controls (text boxes, labels, etc) on the report. If a control is selected,
you'll see the Control Source property but not the Record Source property,
because a control doesn't have a Record Source property. To select the
report you can click that box in the upper left corner as you discovered, or
you can choose Select Report from the Edit menu, or use the keyboard
shortcut Ctrl+R.