I recently updated to Tor Browser 4.0 and found that this new version has a number of oddities in the realm of how it draws its window. Please examine the attached screenshots.

first run

This screenshot shows how the Tor Browser window first shows up on my screen after a fresh install. Note the blank spaces at the bottom of the window (resembling a status bar) and at the right edge. Both of these anomalies go away if I do anything to resize the window, or even just minimize and restore the window (forcing a redraw) - so the inconvenience is minor, but still, this shouldn't be happening.

with CTR

This screenshot shows the changes after installing the Classic Theme Restorer extension and restarting. First, note that the window is considerably shorter than on the first run; this has nothing to do with CTR and happens on the second run even when the first run is shut down without doing anything. Why can't Tor Browser properly save and restore my desired window height? Second, notice that the blank spaces at bottom and right still appear, even now that CTR is creating a new toolbar at the bottom of the window. Third, notice that the old style of main menu button at upper left that was recreated by CTR does not appear to have enough room for the words "Tor Browser". (Unlike the others, this particular anomaly never does resolve itself, no matter what I do.) Am I doing something to cause these strange behaviors? Is there something unusual about my computer that could be causing them? Is there some sort of incompatibility between Tor Browser and CTR that I'm not aware of?

2 Answers 2


The reason Tor Browser does not save/restore changed window sizes is that websites can query your window size, even with JavaScript turned off. This would then act as a persistent identifier (fingerprint).

More generally, changing your window size at all is a bad idea for this very reason, as is installing (most) extensions. Use the defaults, Luke.

  • True, but there are degrees of anonymity. If losing my anonymity could be life-threatening, then first off, I wouldn't be posting here; and second, I'd be sure to use Tor "straight out of the box". However, for most of us, anonymity is a series of trade-offs, and I'm willing (and in a situation where I'm able) to sacrifice a little anonymity for convenience.
    – user1128
    Nov 30, 2014 at 3:52

This is a bug in the current version of Tor Browser Bundle. It has bug number #13142. However all effort and information can be found at #13437. Here you'll also find information when a fix is found.

  • Okay, that explains the blank areas on the screen (and I understand that the problem is way more complicated than it appears at first glance, given that Tor needs to obscure anything that might be usable as tracking info on the other end), but it still doesn't explain the refusal to remember window height (a bug which existed long before this one showed up) or why the "Tor Browser" title doesn't fit in the alloted space for it. Maybe I should have posted these as separate questions.
    – user1128
    Nov 28, 2014 at 18:37

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