Before Firefox 31 I had set the new tab page grid to 13 rows by 2 columns which effectively hid the blank thumbnails while still clearly showing the text of each to click on. Bug 978338 broke that behaviour, resulting in a 3 rows by 2 columns grid. This bug is to make the behaviour dependent upon the values of these prefs: So keep the current height/width ratio of thumbnails, UNLESS: browser.pagethumbnails.capturing_disabled is set to true, AND browser.newtabpage.rows has a value much greater than (at least 3X or 4X) the value of browser.newtabpage.columns upon which the new tab page should revert to the previous behaviour: allowing thumbnails to be clipped vertically (given they are blank anyway)

Either obey browser.newtabpage.rows/columns or remove the prefs. I would prefer they were obeyed.

(In reply to Jesper Hansen from comment #1) > Either obey browser.newtabpage.rows/columns Bug 1005596 was filed to obey the prefs, but specifically only when zoomed out and keeping the ratios without clipping. > Either obey browser.newtabpage.rows/columns > or remove the prefs. I would prefer they were obeyed. Bug 1026561 has been filed to remove the prefs.