Yes -- but only by default! If you go to Tools -> Page Setup -> Zoom -> Sidebar -> Tweaks, and then click on [+] next to Polling Interval to expand the box, a "Bar:" property appears, where you can enter a lower number to set the bar lower. Or just use the arrow buttons next to the field to increase or decrease it. (But note that if you already typed a number, and then use the buttons, it increments from the old number that was overwritten, not from what you typed. (Bugzilla item dating back to 2006, status UNCONFIRMED.))