Instead of explaining this bug in prose form, I'll just list the steps you need to reproduce it.   Begin editing a post (not sure if actually making any changes makes a difference) A wild "An edit has been made to this post" dialog appears! Click on said dialog to refresh the post's content, discarding your edits and taking you out of post-edit mode Edits looks okay (surprised look on face), so I'll just navigate away Are you sure you want to navigate away? You may lose your changes. [OK] [CANCEL]   I can see why this hasn't been caught before; it's kind of uncommon. If you didn't catch the bug: I'm no longer making edits, therefore the "Navigate away" prompt shouldn't show up.
In a certain case, the user will be asked to confirm if he/she wishes to leave the page, due to editing a post, even when he/she has stopped editing.  To reproduce:   Start editing a post (I've only experienced this with a question) Another user finishes editing the post before you and the message "This post has been edited" appears Clicking on the message bar will take you out of editing mode and will show you the updated post from the other user's edits Trying to navigate away from the page will then ask for your confirmation
Understanding divison by monic polynomial in $R[x]$ where $R$ is an arbitrary ring I read "Algebra: Chapter 0" by P.Aluffi. I encountered a topic where it says you can divide any polynomial in $R[x]$($R$ is any ring) by a monic polynomial(that is, a polynomial of the form $x^d + \sum\limits_{i=0}^{d-1} a_i x^{i}$).   It says if $g(x)$ is any polynomial and $f(x)$ is a monic polynomial. Then $\exists \ \ \ q(x), r(x) \in R[x],\: \deg r(x) &lt; \deg f(x): g(x) = f(x)q(x) + r(x).$  I have two questions regarding this:  1) Why $f(x)$ needs to be monic?   2) How can we prove it? The book talk about induction and that if $\deg  g(x) = n &gt; d = deg \ f(x)$, then $\forall a \in R$ we have $ax^n = ax^{n-d}f(x) + h(x)$ for some $h(x): \deg \ h(x) &lt; n$. It's true, but how do I take it from here? How to embed fonts at compile time with pdflatex How can I hover over icons in Ubuntu Dock to see all windows of one application? I'm using Ubuntu 17.10 with GNOME 3. How can I show all open windows of a certain application using the sidebar (aka Ubuntu Dock)? Right now I have to right-click and select "all windows" to see my other open windows.   Is there a quicker way to do this? It seems common that PBX and other telephone hardware use a positive-ground power supply, where the "hot" line is at -48v.  What's the reason for that? Can I hire my kid and start a Roth IRA for him? I own an LLC, of which I am currently the sole member. It's my main source of income.  I am wondering if there is a reason why I could not do the following:   Hire my child as a part-time employee of the LLC, for an annual salary of $5500. Start a Roth IRA for the kid and put the $5500 into it. Deduct the $5500 as a payroll expense for my LLC, thereby reducing my amount of taxable income.   To me, this seems attractive because I'd lower my LLC's tax liability. Meanwhile, my kid would not have to pay any taxes on the $5500 because it is lower than the standard deduction. And by putting the money in a Roth IRA, he'd get an investment that would grow tax-free. It would essentially be like getting the pre-tax benefits of a traditional IRA with the post-tax benefits of a Roth.  The way I see it, I'd win, my kid would win and the IRS would lose, for once.  Is there any reason this wouldn't work? There is no minimum age or income for contributing to a Roth IRA. So as long as I could legally hire my kid, I don't see any obstacles. What should I do when my neural network doesn't learn? I'm training a neural network but the training loss doesn't decrease. How can I fix this?  I'm not asking about overfitting or regularization. I'm asking about how to solve the problem where my network's performance doesn't improve on the training set.    This question is intentionally general so that other questions about how to train a neural network can be closed as a duplicate of this one, with the attitude that "if you give a man a fish you feed him for a day, but if you teach a man to fish, you can feed him for the rest of his life." See this Meta thread for a discussion:   If your neural network does not generalize well, see: How to capture the scene exactly as my eyes can see? As a disclaimer, I must admit this may benefit me (I haven't checked), but probably not as significantly as most others. This issue is also something that has prevented me from answering questions by users with 1 rep in the past, especially if they are poorly fashioned. The Problem New users with a programming question find SO from various methods, such as google. They ask a question with haste, hoping for a quick answer -- which they usually receive. Many of these users have no interest in Stack Overflow itself, but are simply interested in getting the solution they require. As a result of this, they'll check the site regularly for the first day or two until a sufficient answer has been posted. Once they get what they need, they bail; without the required rep or understanding that they should up-vote and select a response as the answer. The Result A great many questions on SO are abandoned by users with no intention of ever coming back. The answer they require has been provided, but for one or more reasons they have neglected their duty of contributing back by way of awarding reputation. The Reach (Since Jeff loves Datum) Some queries on the data dump examine the reach of this 'problem'. The query I used is based on extensions of the following base query; SELECT p1.Id, p1.Score, p1.OwnerUserId, p2.OwnerUserId, p2.Score FROM posts p1  INNER JOIN posts p2 ON (p1.Id=p2.ParentId) LEFT JOIN users ON (p1.OwnerUserId=users.Id) WHERE p2.Score &gt;= 2  AND p2.Score = ( SELECT MAX(p3.Score) FROM posts p3 WHERE p3.ParentId=p1.Id ) AND users.Reputation &lt; 15 AND p1.PostTypeId = 1 AND p1.AcceptedAnswerId = 0  Result: 3,288 Questions by users with under 15 rep which have answers with 2+ up votes that have no accepted answer. Adding: AND (users.LastAccessDate-p1.LastActivityDate) &lt; 604800 // 1 week AND p1.CreationDate &lt; 1249084800 // 1249084800 is 1 week before latest dump data  to the where clause further reveals that 877 questions that have answers with 2+ up votes have no accepted answer, and the owner of the question has not returned since the week the question was asked. Modifying there where clause, and removing the left join: AND p1.OwnerUserId = 0    Reveals a staggering 3,675 questions with answers of 2+ votes by deleted users.  These are questions that were probably answered but the users who did the work can never be recognized. Building off the previous and using an even more restrictive WHERE clause WHERE p2.Score &gt;=5  Still 1,178 posts that can never have an accepted answer. How many posts are there with over 5 up votes that don't provide the correct answer? Modifying the where clause for Reputation to AND users.Reputation = 1  Still reveals 388 questions by users with 1 rep have been abandoned. Solution Similar to how bounty questions work, if a user has abandons the site (not active since x time after the question was asked) with a question that has answers with 2+ up votes, force the answer with the most up votes to be the selected answer. This will reduce the amount of questions that are unanswered, and also give users more of an incentive to answer questions by new users without extra hesitation.  Update Added more statistics for deleted users.  Please feel free to add/remove rules to make this a truly practical feature. Simple request, really.  Can we add a detection for the     Please avoid extended discussions in   comments. Would you like to   automatically move this discussion to   chat?   prompt, so that if one of the users in the "extended discussion" has under 20 rep it doesn't appear?  I think a lot of the users this apply to will have low rep and it may take some back and forth to get good info out of them.  New suggestion: how about if a sufficiently high-rep user is clicking on the link, the low-rep user gets a field promotion sufficient to chat? Low-rep users are particularly prone to post questions to lead in this direction of needing to move to chat. I want to do:  cat update_via_sed.sh | sed 's/old_name/new_name/' &gt; new_update_via_sed.sh   in my program.  But I want to use variables, e.g.  old_run='old_name_952' new_run='old_name_953'   I have tried using them but the substitution doesn't happen (no error). I have tried:  cat update_via_sed.sh | sed 's/old_run/new_run/' cat update_via_sed.sh | sed 's/$old_run/$new_run/' cat update_via_sed.sh | sed 's/${old_run}/${new_run}/' How do I change the shortcut-key of show the unity dash? I don't want to use the Super for that, I want to use Alt+Space instead. What is the difference between a synchronized method and synchronized block in Java? How best to sum up lots of floating point numbers? How to store and preserve film negatives and slides? I bought 35mm dedicated film scanner (Nikon CoolScan III) and I'm planning to digitize old negatives and slides I found at home.  How should I store and preserve these slides and films after I cut them and scan? How to choose best negative pages/sleeves, binders etc. and what to avoid? How does Java's serialization work and when it should be used instead of some other persistence technique? I've been lately trying to learn more and generally test Java's serialization for both work and personal projects and I must say that the more I know about it, the less I like it. This may be caused by misinformation though so that's why I'm asking these two things from you all:  1: On byte level, how does serialization know how to match serialized values with some class?  One of my problems right here is that I made a small test with ArrayList containing values "one", "two", "three". After serialization the byte array took 78 bytes which seems awfully lot for such low amount of information(19+3+3+4 bytes). Granted there's bound to be some overhead but this leads to my second question:  2: Can serialization be considered a good method for persisting objects at all? Now obviously if I'd use some homemade XML format the persistence data would be something like this  &lt;object&gt;     &lt;class="java.util.ArrayList"&gt;     &lt;!-- Object array inside Arraylist is called elementData --&gt;     &lt;field name="elementData"&gt;         &lt;value&gt;One&lt;/value&gt;         &lt;value&gt;Two&lt;/value&gt;         &lt;value&gt;Three&lt;/value&gt;     &lt;/field&gt; &lt;/object&gt;   which, like XML in general, is a bit bloated and takes 138 bytes(without whitespaces, that is). The same in JSON could be   {     "java.util.ArrayList": {         "elementData": [             "one",             "two",             "three"         ]     } }   which is 75 bytes so already slightly  smaller than Java's serialization. With these text-based formats it's of course obvious that there has to be a way to represent your basic data as text, numbers or any combination of both.  So to recap, how does serialization work on byte/bit level, when it should be used and when it shouldn't be used and what are real benefits of serialization besides that it comes standard in Java? Workflow for developing add-on/script I'm trying to figure out a good workflow for developing scripts and add-ons in Blender. Here's what I'm currently doing as I try my luck with a PyNode add-on:   Open blender Create a text editor panel Open my script (external text file) Edit my script in a nice external editor Reload the script Save the .blend file Run the script   Now that I can see what my code does, this Blender instance has been modified, so I can't (make changes to my script and) run my script again. So I do this:   Close blender Open blender with the .blend from step 6 and repeat steps 4-7, over and over and over..   Is there a better workflow for this sort of thing? How do I deal with "unauthenticated sources" errors in the Software Center? Integer solutions for $x^2-y^3 = 23$. As the title stated, I am wondering the integers $x,y$ that satisfy the equation $x^2-y^3 = 23$. Let $A$ and $B$ be two matrices which can be multiplied. Then $$\operatorname{rank}(AB) \leq \operatorname{min}(\operatorname{rank}(A), \operatorname{rank}(B)).$$   I proved $\operatorname{rank}(AB) \leq \operatorname{rank}(B)$ by interpreting $AB$ as a composition of linear maps, observing that $\operatorname{ker}(B) \subseteq \operatorname{ker}(AB)$ and using the kernel-image dimension formula. This also provides, in my opinion, a nice interpretation: if non-stable, under subsequent compositions the kernel can only get bigger, and the image can only get smaller, in a sort of loss of information.  How do you manage $\operatorname{rank}(AB) \leq \operatorname{rank}(A)$? Is there a nice interpretation like the previous one? What is the setting in bash for globbing, to control whether * matches dot files I was surprised recently when I did something like mv ./* ../somedirectory and found that files like .gitignore were not moved.  I do most of my work in zsh on OS X, and this surprise bit me in bash on CentOS.  I tried bash on OS X and found the same behavior: * does not match dot files.  This seems very undesirable to me, but apparently it's the bash default.  (It may be the zsh default too for all I remember, but I may have changed it years ago in my .zshrc and forgotten it ever worked differently.)  How can I configure bash to behave as I expected: for * to match all files, and not ignore dot files.  In case this is at all unclear, here's how to reproduce it    cd /tmp mkdir {t,d}est touch test/{.,}{1,2,3,4,5,6,7} ls -hal test mv test/* dest ls -hal test     # notice dot files are still there ls -hal dest     # notice only some files were mv'ed