Why are only some questions highlighted? When I am visiting , I see only some questions as highlighted. Why so?  "Ruby on rails" is added in my favorite tag list. So it should highlight all the questions..  A preview (see full image ):
Why do some questions in question lists have a yellow background? On SO, when I'm scrolling through "questions" some have a yellow background.  Is this intuitive to everyone but me?  What is the yellow background trying to tell me about this particular question?
How to lock compiled Java classes to prevent decompilation? How do I lock compiled Java classes to prevent decompilation?  I know this must be very well discussed topic on the Internet, but I could not come to any conclusion after referring them.  Many people do suggest obfuscator, but they just do renaming of classes, methods, and fields with tough-to-remember character sequences but what about sensitive constant values?  For example, you have developed the encryption and decryption component based on a password based encryption technique. Now in this case, any average Java person can use  to decompile the class file and easily retrieve the password value (defined as constant) as well as  and in turn can decrypt the data by writing small independent program!  Or should such sensitive components be built in native code (for example, VC++) and call them via ? Can you create a strong blockcipher with small blocksize, given a strong blockcipher of conventional blocksize? Visually stunning math concepts which are easy to explain Since I'm not that good at (as I like to call it) 'die-hard-mathematics', I've always liked concepts like the  or the , which are easy to understand and explain but are mathematically beautiful at the same time.  Do you know of any other concepts like these? We have a few Win32 applications (coded in Delphi 2006) where sometimes the user gets an error message saying "System Error. Code: 8. Not enough storage is available to process this command.".  From the stacktrace it looks like it is always during CreateWnd call  Main ($1edc): 004146cc +070 app.exe SysUtils               RaiseLastOSError 00414655 +005 app.exe SysUtils               RaiseLastOSError 004ce44c +130 app.exe Controls               TWinControl.CreateWnd 00535a72 +022 app.exe cxControls             TcxControl.CreateWnd 004ce82a +016 app.exe Controls               TWinControl.CreateHandle 00553d21 +005 app.exe cxContainer            TcxContainer.CreateHandle 00586ef1 +005 app.exe cxEdit                 TcxCustomEdit.CreateHandle 005c331d +005 app.exe cxDropDownEdit         TcxCustomDropDownEdit.CreateHandle 004ceaf0 +074 app.exe Controls               TWinControl.UpdateShowing 004ceb1e +0a2 app.exe Controls               TWinControl.UpdateShowing 004cebdc +03c app.exe Controls               TWinControl.UpdateControlState 004d118a +026 app.exe Controls               TWinControl.CMVisibleChanged 004cb713 +2bb app.exe Controls               TControl.WndProc 004cf569 +499 app.exe Controls               TWinControl.WndProc 004b727d +4c1 app.exe Forms                  TCustomForm.WndProc 004cb3a0 +024 app.exe Controls               TControl.Perform 004c9f6a +026 app.exe Controls               TControl.SetVisible 004b6c46 +03a app.exe Forms                  TCustomForm.SetVisible 004baf1b +007 app.exe Forms                  TCustomForm.Show 004bb151 +14d app.exe Forms                  TCustomForm.ShowModal 007869c7 +0d3 app.exe UfrmPrice      770 +19 TfrmPrice.EditPrice 0078655d +009 app.exe UfrmPrice      628  +0 TfrmPrice.actNewBidExecute 00431ce7 +00f app.exe Classes                TBasicAction.Execute 004c2cb5 +031 app.exe ActnList               TContainedAction.Execute 004c397c +050 app.exe ActnList               TCustomAction.Execute 00431bb3 +013 app.exe Classes                TBasicActionLink.Execute 004af384 +090 app.exe Menus                  TMenuItem.Click 004b059f +013 app.exe Menus                  TMenu.DispatchCommand 004b16fe +082 app.exe Menus                  TPopupList.WndProc 004b164d +01d app.exe Menus                  TPopupList.MainWndProc 004329a8 +014 app.exe Classes                StdWndProc 7e4196b2 +00a USER32.dll                     DispatchMessageA 004bea60 +0fc app.exe Forms                  TApplication.ProcessMessage 004bea9a +00a app.exe Forms                  TApplication.HandleMessage 004becba +096 app.exe Forms                  TApplication.Run 008482c5 +215 app.exe AppName        129 +42 initialization   I've never been able to get to the bottom of what causes this and as it happens fairly seldom I haven't been to concerned, but I would like to find out what causes it and hopefully rectify it...  EDIT: Full Stacktrace  EDIT 2: More info... The client who experienced this today has had my app installed for about 4 months and it is running on his PC 8 hours a day. The problem only appeared today and kept reappearing even though he killed my app and restarted it. None of the other apps on his system behaved strangely. After a reboot the problem goes away completely. Does this point towards the heap shortage that Steve mentions?  EDIT 3: Interesting msdn blog post  and  on the topic of the desktop heap. Though I'm not sure whether this is the cause of the problem it certainly looks likely. I'm studying for actuarial exams, but I always pick up mathematics books because I like to challenge myself and try to learn new branches.  Recently I've bought Topology by D. Kahn and am finding it difficult.  Here is a problem that I think I'm am answering sufficiently but any help would be great if I am off.  If $d$ is a metric on a set $S$, show that  $$d_1(x,y)=\frac{d(x,y)}{1+d(x,y)}$$ is a metric on $S$.  The conditions for being a metric are $d(X,Y)\ge{0}, d(X,Y)=0$ iff $X=Y$, $d(X,Y)=d(Y,X)$, and $d(X,Y)\le{d(X,Z)+d(Z,Y)}$.  Thus, we simply go axiom by axiom.  1)  Since both $d(x,y)\ge{0}$ and $1+d(x,y)\ge{0},$ it is clear that $d_1(x,y)\ge{0}$.  (Is this a sufficient analysis?) 2) $d_1(x,x)=\frac{d(x,x)}{1+d(x,x)}=\frac{0}{1+0}=0$. 3) $d_1(x,y)=\frac{d(x,y)}{1+d(x,y)}=\frac{d(y,x)}{1+d(y,x)}=d_1(y,x).$ 4) $d_1(x,y)=\frac{d(x,y)}{1+d(x,y)}\le{\frac{d(x,z)+d(z,y)}{1+d(x,z)+d(z,y)}}=\frac{d(x,z)}{1+d(x,z)+d(z,y)}+\frac{d(z,y)}{1+d(x,z)+d(z,y)}\lt\frac{d(x,z)}{1+d(x,z)}+\frac{d(z,y)}{1+d(z,y)}=d_1(x,z)+d_1(z,y).$  However, #4 is strictly less, not less than or equal to, according to my analysis, so where did I go wrong? about://(null) popup? I encountered a popup similar to this one this morning while checking the weather report at  in Safari, though I have not been able to reproduce it.  The title is "about://(null)" and the text "Why you no play Candy Crush!!"  The popup occurred twice.  I tapped Cancel both times.  I suspect the source of this is rogue JavaScript in an ad network, judging from the fact that the screenshot below shows it in an ad-supported application, and when I saw it, I was on an ad-supported website.  My phone is not jailbroken.  I'm wondering if anyone is able to identify the source of the popup definitively.  Speculation is running rampant on Apple's support communities and elsewhere, from push notifications (delete Facebook and all your games!) to carrier notifications (which don't work on iPod Touches…), and my gut tells me little of it is helpful.  But I could also be very wrong.  (This is not my screenshot; it comes from .)    UPDATE 1: The Candy Crush people have this to say, but I'm not (yet) convinced there's actually something installed that is to blame:   UPDATE 2: Just reproduced it in the iOS Simulator while clicking around woodtv.com, but I'm not sure how to track it down further from here. Moment generating function (MGF) of the ratio distribution $\displaystyle\frac{X}{Y}$ If we know the moment generating functions (MGFs) of the random variables $X$ and $Y$ to be $M_{X}(s)$ and $M_{Y}(s)$, respectively. The MGF of the sum $X+Y$ will $M_{X}(s) \cdot M_{Y}(s)$.  So what is the MGF of the ratio distribution $\displaystyle\frac{X}{Y}$? Restoring open software after a restart event in windows I find that at the end of a long day, I sometimes have a large number of programs running. All which I will need to use tomorrow. Normally, this isn't an issue, I can simply lock the machine and come back tomorrow. My problem arrises when windows update launches in the middle of the night and force restarts my computer. That in turns closes all my open software. I of course save everything regularly so I don't loose anything, but I waste time reopening all of those resources whenever there is a restart.   [EDIT]  I should clarify that I still want to be able to restart my computer when an update comes down. Preventing the restart only delays the problem until later. I should have been more specific in that I want to be able to recover my working environment after a restart for any reason. Things like scheduled maintence, power loss, updates, and software installs.  [EDIT]  I can't simply have them setup to launch at startup becasuse those files change from week to week. So I need something that monitors what I have open, and gives me the option to "recover" those software sessions when I log back in.  Anyone have any suggestions on what I can do? I'd even be willing to purchase software to do this for me if that is the only option.  Thanks Someone mentioned it in the IRC as the slicing problem. Today, on C.SE, I reviewed some 'Late Answers' and First Posts.  I was not even near my daily vote limit.  And yet, I was given a message that said      comments disabled on deleted / locked posts / reviews   It seems I was not the only one either:   The workaround, of course, was simply to go back and provide the guidance - but was this a design or a bug?  If it is design, why would you want to discourage the feedback? Especially with first posts, there is often a high percentage of 'didn't read the FAQ' usage, which can best be addressed by gently providing guidance. (e.g. "Unfortunately, this doesn't answer the question" or "This reads like a comment" or "This really isn't on-topic here - can I suggest you checkout our [faq]" etc...)  Timely first post guidance goes a long way towards making good users.   If it was a bug, was other functionality silently rolled out? Determine if a set of tiles on a grid forms an enclosed shape How can I restore configuration files? I would like to restore LightDM to its default state, because for some reason /etc/lightdm/unity-greeter.conf is now an empty file.  Deleting /etc/lightdm/unity-greeter.conf and then running sudo apt-get install --reinstall unity-greeter doesn't create a new config file as you might expect.   How can I restore a missing config file? Let's say you have a few expressions like the following:  $$\begin{array}((x+17)^2 \\ x^2 + 34x + 289 \end{array} \\ 288 + \frac{x^2}{2} + \frac{x^2}{2} + 34x + 1 \\ [...] $$  You get the idea: there's an infinite number of ways of representing the same expression. The challenge is that my application is validating answers to math problems, input by math students practicing a certain concept. I'd like to make sure that whenever they submit an answer, the checker is completely insensitive to the issues of ordering, simplification, formatting etc. which would be plain frustrating. I'd also ideally like to support more than one variable such as x, y, z in the same expression.  What's a reliable way to check that two expressions are the same? The most brute force way I can think of would be to just plug a number into each variable of each expression and see what the result is.  I have a hunch however that there might be ways of getting false positives this way. That, and I might be either missing something really obvious about this, or there might be a better way of doing the comparison.  Would love to hear what you think. If nonempty, nonsingleton $Y$ is a proper convex subset of a simply ordered set $X$, then $Y$ is ray or interval? This is from Exercise 7 in p. 92 in Munkres's Topology.  Except for the trivial cases such as $Y$ is empty set or singleton, it seems if $Y$ is convex in an simply ordered set $X$ then $Y$ is interval or ray.  But I cannot start my proof because I cannot use $\sup$ or $\max$ functions.  What should I do? Qualcomm Atheros QCA6174 802.11ac Wireless Network Adapter [168c:003e] (rev 32) can't enable wi-fi How to remove comma and "and" before institutional last author after compiling BibTeX I have the following BibTeX entry:  @article{pubmed18800157,     author = {Heng, T.S. and Painter, M.W. and Immunological Genome Project Consortium},     title = {The {I}mmunological {G}enome {P}roject: networks of gene expression in immune cells.},     journal = {Nat. Immunol.},     pages = {1091-1094},     volume = {9},     number ={10},     year = {2008}, }, %\bibliographystyle{unsrt}   When the bibliography is generated, it puts comma a the end of the author:   Notice the comma after M.W. Painter. Is there a way to remove it? Evaluate $\int \frac{1}{(x^2+1)^2}dx$ $$\int \frac{1}{(x^2+1)^2}\mathrm dx$$ Look simple, but I stuck a little bit. What method is better in this situation? Please, help. "The thing is, is that..." Using \footnote in a figure's \caption Maybe this is an easy one, but I struggled with this now too long :)  I want to have a footnote in a caption of a figure, see the example.   \begin{figure}[!ht]   \caption{a figure caption\footnote{where i got it from}}   \label{somelabel}   \begin{center}        \pgfuseimage{...}   \end{center} \end{figure}   The compilation error reads as follows  ! Argument of \@caption has an extra }. &lt;inserted text&gt;              \par  l.192 ...i got it from}}   The actual tex code for my figure with the answer of Leo  \pgfdeclareimage[width=6cm]{aba.medcenter}{aba.medcenter}  \begin{figure}[!ht]   \begin{minipage}{\textwidth}     \caption[Medcenter Monthly Medication System]{Medcenter\textsuperscript\textregistered Monthly Medication System\footnote{Quelle Bild: http://www.amazon.com/dp/B000RZPL0M}}     \label{aba.medcenter}     \begin{center}       \pgfuseimage{aba.medcenter}     \end{center}   \end{minipage} \end{figure}   leads to the error  ! LaTeX Error: Command \itshape invalid in math mode.   in the same line. If I comment out the foot note, everything compiles fine. \textsuperscript\texttrademark isn't the problem, too. If I have a sentence that starts with additionally, finally, consequently, etc. do I always have to put a comma after it? Or is there a different rule?