once again i've mucked up my LR settings, and i don't know how to ask Dr. Google how to fix it ;p
you know how there are three "panels" in LR? one on the left, one on the right, and one on the bottom... the bottom one is a "film strip" showing thumbnail sizes for all images in the current file...
for the panels, you can set it so that they are always showing, or only showing when "moused" over... well - somehow i've lost the ability to have the film strip always showing... the little tab thing that should allow me to toggle back and forth seems to have disappeared...
Right-click and set it to Manual and then click the arrow to show it.
Surprise, there is a fourth panel. F5 toggles the top panel