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1. • CommentRowNumber1.
   • CommentAuthorRodMcGuire
   • CommentTimeFeb 16th 2024
   • (edited Feb 16th 2024)
   • PermaLink
   Author: RodMcGuire
   Format: MarkdownItexA few people have noticed that nLab pages rendered by Firefox sometimes leave out some math symbols. This can be annoying but can be fixed by reloading the page. This happened to me today when I opened [[functoriality of categories of presheaves]]. That page should have 2 MathML expressions near the top which should be rendered as "$PSh(C, D)$" and "$F : C \to C'$". Today they were rendered as "$PSh C, D$" and "$F : C\: C'$" except that their layout was more like room had been reserved for the missing characters which were just invisible. I decided to right click on one of those and use the inspector to see what Firefox was trying to render. But when I did and the inspector panel came up both items became correctly rendered. I think this means that there is some sort of rendering timing bug in FF that makes it think it has fully rendered characters when it hasn't, and it is no fault of the nLab page source or any extensions installed. I don't know how to get Mozilla to address this usually not repeatable bug. Firefox version: 122.0.1, Windows 10 version: 22H2 19045.4046

   A few people have noticed that nLab pages rendered by Firefox sometimes leave out some math symbols. This can be annoying but can be fixed by reloading the page.

   This happened to me today when I opened functoriality of categories of presheaves. That page should have 2 MathML expressions near the top which should be rendered as “$PSh(C, D)$” and “$F : C \to C'$”. Today they were rendered as “$PSh C, D$” and “$F : C\: C'$” except that their layout was more like room had been reserved for the missing characters which were just invisible. I decided to right click on one of those and use the inspector to see what Firefox was trying to render. But when I did and the inspector panel came up both items became correctly rendered.

   I think this means that there is some sort of rendering timing bug in FF that makes it think it has fully rendered characters when it hasn’t, and it is no fault of the nLab page source or any extensions installed.

   I don’t know how to get Mozilla to address this usually not repeatable bug.

   Firefox version: 122.0.1, Windows 10 version: 22H2 19045.4046

2. • CommentRowNumber2.
   • CommentAuthorvarkor
   • CommentTimeFeb 16th 2024
   • PermaLink
   Author: varkor
   Format: MarkdownItexBy the way, you don't need to refresh the page to fix the issue. Highlighting the missing text will also render them.

   By the way, you don’t need to refresh the page to fix the issue. Highlighting the missing text will also render them.

3. • CommentRowNumber3.
   • CommentAuthorRodMcGuire
   • CommentTimeFeb 17th 2024
   • PermaLink
   Author: RodMcGuire
   Format: MarkdownItexIf some reader here encounters this behavior could you try and report back if either of these things make the invisible characters appear. * scroll the bad math off the page and then scroll back. * resize the window down somewhat small to change how the text is broken into lines and then resize it back.

   If some reader here encounters this behavior could you try and report back if either of these things make the invisible characters appear.

   • scroll the bad math off the page and then scroll back.

   • resize the window down somewhat small to change how the text is broken into lines and then resize it back.

4. • CommentRowNumber4.
   • CommentAuthorUrs
   • CommentTimeFeb 17th 2024
   • (edited Feb 17th 2024)
   • PermaLink
   Author: Urs
   Format: MarkdownItexThanks for looking into this old problem! Yes, I see this effect a lot, and yes, all of the steps mentioned (scrolling, resizing, highlighting, probably anything that forces the browser to re-render) make the missing symbols appear on my system (Firefox on Windows). Trying now to get some statistics: When I keep opening the page (not re-loading, but opening afresh in a new window), many dozen of times right now, first I saw the error something like 9 out of 10 times, and then decreasing in rate, now it is about 1 out of 2 times.

   Thanks for looking into this old problem!

   Yes, I see this effect a lot, and yes, all of the steps mentioned (scrolling, resizing, highlighting, probably anything that forces the browser to re-render) make the missing symbols appear on my system (Firefox on Windows).

   Trying now to get some statistics: When I keep opening the page (not re-loading, but opening afresh in a new window), many dozen of times right now, first I saw the error something like 9 out of 10 times, and then decreasing in rate, now it is about 1 out of 2 times.

5. • CommentRowNumber5.
   • CommentAuthorRodMcGuire
   • CommentTimeFeb 17th 2024
   • PermaLink
   Author: RodMcGuire
   Format: MarkdownItexThe effect may depend on how much memory Firefox is using and what sort of background activity is going on in other tabs which makes it hard to duplicate. All of this is complicated by the renderer being rewritten to take advantage of multi-core CPUs with lots of different threads communicating and synchronizing with each other. One other thing I noticed (once) is that when it happens twice on opening the same page the two bad pages look the same with the same errors. FF also appears to hate $\to$ characters which often become invisible. I haven't verified that if one $\to$ is invisible then all are. The next tine someone notices this try having a look at the error log in the page's Web Console. Pressing Cntrl-Shift-k will activate it (each page has its own console). Maybe there will be an error message about some abnormal termination. I just looked at the console of a page that may have been bad and all I see is: > MathML length value “verythinmathspace” is deprecated and will be removed at a future date.

   The effect may depend on how much memory Firefox is using and what sort of background activity is going on in other tabs which makes it hard to duplicate. All of this is complicated by the renderer being rewritten to take advantage of multi-core CPUs with lots of different threads communicating and synchronizing with each other.

   One other thing I noticed (once) is that when it happens twice on opening the same page the two bad pages look the same with the same errors. FF also appears to hate $\to$ characters which often become invisible. I haven’t verified that if one $\to$ is invisible then all are.

   The next tine someone notices this try having a look at the error log in the page’s Web Console. Pressing Cntrl-Shift-k will activate it (each page has its own console). Maybe there will be an error message about some abnormal termination.

   I just looked at the console of a page that may have been bad and all I see is:

   MathML length value “verythinmathspace” is deprecated and will be removed at a future date.

6. • CommentRowNumber6.
   • CommentAuthorRodMcGuire
   • CommentTimeFeb 20th 2024
   • PermaLink
   Author: RodMcGuire
   Format: MarkdownItexI encountered my latest rendering error opening [[joint and marginal probability]]. Near the top of the page is supposed to appear the centered equation $$P(A,B) \ne P(A)\,P(B).$$ however all the parentheses were invisible. Scrolling that text off the page and back didn't fix it (maybe because it was in a fixed environment?). Selecting part of the math and then unhighlighting made only the selected invisible characters visible, not the unselected ones. Sizing the window down small and resizing didn't fix it until I tried again and scrolled the small window to show that equation. The Web Console contained the additional message > Opening multiple popups was blocked due to lack of user activation. page_helper.js:198:7 which comes from nLab Javascript. That may have arisen when I was clicking to select or deselect and the code thought I was trying to ask for LaTeX source. Urs - you appear to encounter this problem most often. Have you ever seen it in the nForum or nCafe (which also appear to use native MathML or only at the nLab?

   I encountered my latest rendering error opening joint and marginal probability. Near the top of the page is supposed to appear the centered equation

   $$P(A,B) \ne P(A)\,P(B).$$

   however all the parentheses were invisible.

   Scrolling that text off the page and back didn’t fix it (maybe because it was in a fixed environment?). Selecting part of the math and then unhighlighting made only the selected invisible characters visible, not the unselected ones. Sizing the window down small and resizing didn’t fix it until I tried again and scrolled the small window to show that equation.

   The Web Console contained the additional message

   Opening multiple popups was blocked due to lack of user activation. page_helper.js:198:7

   which comes from nLab Javascript. That may have arisen when I was clicking to select or deselect and the code thought I was trying to ask for LaTeX source.

   Urs - you appear to encounter this problem most often. Have you ever seen it in the nForum or nCafe (which also appear to use native MathML or only at the nLab?

7. • CommentRowNumber7.
   • CommentAuthorUrs
   • CommentTimeFeb 20th 2024
   • PermaLink
   Author: Urs
   Format: MarkdownItexI think I only see this effect on the nLab.

   I think I only see this effect on the nLab.

8. • CommentRowNumber8.
   • CommentAuthorRodMcGuire
   • CommentTimeFeb 20th 2024
   • PermaLink
   Author: RodMcGuire
   Format: MarkdownItexI just opened [[joint and marginal probability]] again and encountered the error. (invisible parentheses) This time I tried scrolling not just until the bad equation was off the page but until I encountered more math parentheses. When I scrolled back to the problem equation it was entirely visible.

   I just opened joint and marginal probability again and encountered the error. (invisible parentheses)

   This time I tried scrolling not just until the bad equation was off the page but until I encountered more math parentheses. When I scrolled back to the problem equation it was entirely visible.

9. • CommentRowNumber9.
   • CommentAuthorTim_Porter
   • CommentTimeFeb 20th 2024
   • PermaLink
   Author: Tim_Porter
   Format: MarkdownItexSince you mentioned it, Rod, I was curious and clicked on the link in your first line to view the page. It came up without parentheses. I refreshed the page (cmd-R on Firefox on a Macbook) and the parenthese appeared. I hope this helps sort out the problem

   Since you mentioned it, Rod, I was curious and clicked on the link in your first line to view the page. It came up without parentheses. I refreshed the page (cmd-R on Firefox on a Macbook) and the parenthese appeared. I hope this helps sort out the problem

10. • CommentRowNumber10.
    • CommentAuthorRodMcGuire
    • CommentTimeFeb 21st 2024
    • PermaLink
    Author: RodMcGuire
    Format: MarkdownItexUgh. There may be two related issues involved. Right now on the pages [[joint and marginal probability]] and [[functoriality of categories of presheaves]] which I've gotten displayed correctly, if I perform a "hard refresh" (Cntrl-Shift-r) they display invisible MathML characters. However if I switch to a different tab and then switch back all of the characters have become visible. In earlier tests the invisible characters persisted under tab switching. I've been unable to find any Mozilla documentation and what a hard refresh does other than saying it bypasses the cache by reloading all files associated with the page. It also seems to be clearing out some state information associated with the page.

    Ugh. There may be two related issues involved.

    Right now on the pages joint and marginal probability and functoriality of categories of presheaves which I’ve gotten displayed correctly, if I perform a “hard refresh” (Cntrl-Shift-r) they display invisible MathML characters. However if I switch to a different tab and then switch back all of the characters have become visible. In earlier tests the invisible characters persisted under tab switching.

    I’ve been unable to find any Mozilla documentation and what a hard refresh does other than saying it bypasses the cache by reloading all files associated with the page. It also seems to be clearing out some state information associated with the page.