Thank you for sharing your add-ons list.

Since you have the "Element Hiding Helper for Adblock Plus" and "Yet Another Remove It Permanently" extensions, I wonder whether the overlay got accidentally hidden. Is there a way to check that, for example, an icon or right-click menu that would show you whether anything is being hidden on Netflix?

Separate question: does your system have a touchscreen -- not a touch pad in place of a mouse, but the actual display?

Firefox 52 turned on touchscreen auto-detection on the Windows version of Firefox, and that causes strange issues on some sites. Here's where you find that setting if you want to experiment with it:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste touch and pause while the list is filtered

(3) Double-click the dom.w3c_touch_events.enabled preference and edit the value to 0 (zero) and then click OK. The options are:

• 0 => disable touch
  
• 1 => enable touch
  
• 2 => auto-detect whether the system supports touch (default in Fx52)

I don't know whether that will take effect immediately or after you exit and start Firefox up again. Does that have any effect of selecting by touch?

Oh my goodness, changing dom.w3c_touch_events.enabled to 0 worked, and it took effect immediately. (And I don't have a touch screen.) It fixed some other weird issues on my own website, too, which I had suspected were related. Thank you so much for your help!

Separate question: If this happened to me, it must be happening to other people, too. It seems like the autodetection might not be working properly?

Thanks for reporting back.

I think the problem is when a page has elements set up for touch interaction, Firefox may be ignoring events like "hover" or "mouseover" that are not valid on a touch interface even when the user actually is using a mouse. That's my theory, but as a person who doesn't have a touchscreen, I'm not in a good position to do the research...

I have no idea why Firefox would think your system has a touch screen if it doesn't. Perhaps there's an odd setting in Windows somewhere. I didn't think it would be an issue with Windows 7; usually the touch issues are on Windows 8.1 and Windows 10.

I noticed another config thing: dom.w3c_touch_events.expose, which has user set, boolean, true. I never touched it, however. All the other "touch" preferences have the default values.

What do you think? I'm nervous about changing it without more information.

It's usually safe to restore default settings. You can right-click > Reset it. If interfaces stop working normally with the mouse, you can switch it back, but I don't think it should be necessary.

I tried resetting it, and it set it to an empty string. When I reopened about:config, it was gone, strangely. So I added it back and tried setting it to false and then to true. None of this had any effect on anything.

So now I'm having a separate problem with my own website. I have a bunch of images, and when you hover on an image, a dark gray overlay appears. Then if you click, it's supposed to go to a page with more information. But clicking displays an empty page now. I don't know if this is related to the touch thing or to upgrading to FF 53.0. It still works in Internet Explorer.

Maybe I should post this as a separate question?

Oh, I tried temporarily putting dom.w3c_touch_events.enabled back to 2, and I still get the blank page when clicking an image (but no dark gray overlay, like it's supposed to have).

Artemisia_ said

So now I'm having a separate problem with my own website. I have a bunch of images, and when you hover on an image, a dark gray overlay appears. Then if you click, it's supposed to go to a page with more information. But clicking displays an empty page now. I don't know if this is related to the touch thing or to upgrading to FF 53.0. It still works in Internet Explorer.

Maybe I should post this as a separate question?

Yes, a separate thread is a good idea, and maybe you can give a link to a page where someone can see whether they can reproduce the problem.

Artemisia_ said

I tried resetting it, and it set it to an empty string. When I reopened about:config, it was gone, strangely. So I added it back and tried setting it to false and then to true. None of this had any effect on anything.

It turns out the dom.w3c_touch_events.expose setting was made obsolete by the other setting (which you can see does have an obvious effect), and was just some clutter that wasn't doing anything either way.

Just posting an update -- the separate problem has gone away. It turned out that clicking an image went to the wrong URL in Firefox, but it went to the correct URL in Internet Exporer. Now the problem has gone away, so I'm guessing it was a problem on the website hoster's server side?