I have Ubuntu 17.10. When I enable "Power Saving / Blank screen" and screen locks after N minutes, all running applications shut down. Is it normal? If no how can I fix it?
There is a very bad problem with the "Blank screen" function in Ubuntu 17.10. I refer to the setting accessed via Settings->Power->Blank Screen. This seems to actually perform a screen lock, since I need to enter my password after un-blanking the screen. (However, given the behavior described below it's not clear exactly what this function actually does - maybe it just logs you out? maybe it reboots the machine?)  The problem is that a simple screen lock, which one would expect to lock the screen without affecting the state of any applications, in fact closes all applications that are open when the screen lock activates. In other words, if you have the screen lock set to 5 minutes, and you walk away from your machine to get a sandwich or whatever, when you come back and unlock the machine all your apps have closed without saving their state. So far, the only work-around I have found is to entirely disable screen locking in Ubuntu 17.10. My question is, how can this be fixed so that screen locking works properly - that is: the screen locks on schedule after a period of inactivity, and when unlocked all applications that were running are still running?  I am asking a new question for the following reasons:  1) The existing answers to (and comments on)  do not address the issue, and in fact misrepresent the actual problem in ways that make me think the comment writers have not understood what is happening;  2) I cannot usefully address that question because I do not have sufficient reputation to either upvote the question or comment on it, and I cannot answer the question because I have no idea why this problem occurs;  3) I will probably never achieve a reputation of 15, much less 50, on StackExchange. Which is fine, that's not among my life goals.  4) But this question is important and deserves to be addressed. It is a drastically unacceptable bug.
It looks like this guy  without even knowing it.  I don't get the impression that he was trying to harm anyone with this process.  What about a warning message that triggers after a person upvotes (or downvotes) the same person X times within Y time span (with X and Y being thresholds that are well below the limit that actually results in a vote fraud reversal)?  Say, twice within 15 minutes?  Maybe display a warning pop-up that says:     Whoa, Camel!  It looks like you're starting to perform serial voting on a particular user.  Did you know that    I have little doubt that this guy would have stopped had he been (gently) warned.  Perhaps others will stop, too. No hats on the mobile version? How to tell the order of a Feynman diagram? How can we know the order of a Feynman diagram just from the pictorial representation?  Is it the number of vertices divided by 2?  For example, I know that electnro-positron annihilaiton is first order:   So what's the order of, for instance, a radiative penguin diagram (below) ? I'm using  to go through JavaScript, and it's returning many suggestions to replace == (two equals signs) with === (three equals signs) when doing things like comparing idSele_UNVEHtype.value.length == 0 inside of an if statement.  Is there a performance benefit to replacing == with ===?   Any performance improvement would be welcomed as many comparison operators exist.  If no type conversion takes place, would there be a performance gain over ==? Cannot login to chat.meta.stackexchange.com; server error when trying to access chat homepage I just recreated my MSE account after having deleted it a few years ago. Now, I'm trying to log in to Meta Stack Exchange Chat, and whenever I try to do so, it just fails silently and I'm still logged out.  Additionally, in the same browser session that I'm supposedly logged out, I get a server error when accessing the chat homepage or the chat profile page of any user. I don't get any errors when trying to access any of these pages in a private session. I also was able to sign in to Stack Exchange Chat and Stack Overflow Chat without problems, since my accounts on SO and my parent site for SE chat haven't been deleted.  I think it might be because it's trying to sign me in to my old chat profile, which was not deleted, but that is associated to my old, deleted site account, which clash and thus cause it to fail. I am stuck in a question for Algebraic Structures:  I need to prove: If given any ring $R$, for any $a$ in $R$ $a\cdot a=0$ then $a+a=0$.  (of course $+$, $*$ and $0$ regarding $R$)  I didn't find any question regarding this question. Python Flask shutdown event handler Inheritance of static members in PHP In PHP, if a static attribute is defined in the parent class, it cannot be overridden in a child class. But I'm wondering if there's any way around this.   I'm trying to write a wrapper for someone else's (somewhat clunky) function. The function in question can be applied to lots of different data types but requires different flags and options for each. But 99% of the time, a default for each type would suffice.  It would be nice if this could be done with inheritance, without having to write new functions each time. For example:  class Foo {     public static $default = 'DEFAULT';      public static function doSomething ($param = FALSE ) {         $param = ($param === FALSE) ? self::$default : $param;         return $param;     } }  class Bar extends Foo {     public static $default = 'NEW DEFAULT FOR CHILD CLASS'; }  echo Foo::doSomething() . "\n";  // echoes 'DEFAULT'  echo Bar::doSomething() . "\n";  // echoes 'DEFAULT' not 'NEW DEFAULT FOR CHILD CLASS'  // because it references $default in the parent class :( Can't install experimental modules Adding Vertical Reference in Python to ArcGIS feature dataset Packet sniffing in Python (Windows) What is the best way to sniff network packets using Python?  I've heard from several places that the best module for this is a module called Scapy, unfortunately, it makes python.exe crash on my system. I would assume that it's just a problem with how I installed it, except that many other people have told me that it doesn't work particularly well on Windows. (If anyone is interested, I'm running Windows Vista, which might affect things).  Does anyone know of a better solution?  UPD:  After reading the answer telling me to install PyPcap, I messed around with it a bit and found out that Scapy, which I had tried using, was telling me to install PyPcap as well, except that it's a modified version for it's use. It was this modified PyPcap that was causing the problem, apparently, since the example in the answer also caused a hang.  I installed the original version of PyPcap (from Google's site), and Scapy started working fine (I didn't try many things, but at least it didn't crash as soon as I started sniffing). I sent a new defect ticket to the Scapy developers: , hope they can do something with it.  Anyways, just thought I'd let y'all know. According to Wikipedia      extra disks should not be mounted in /mnt/ according to the first link, but doesn't seams so according to the second link.  Both say thought that they shouldn't be in /media.  Question  So where should extra permanent disks be mounted? Is there a test to determine whether solder is leaded or lead-free? Perhaps conductivity/resistance? When a function has a specific-size array parameter, why is it replaced with a pointer? When I want to move a file to the Trash, Nautilus give me an message saying this:     You can't move example.file to the trash can. Do you want to remove it immediately?   I can give you this photo but it's in Spanish He will understand that I was not joking.   He will understand I was not joking.  Which of the sentences is correct? Are there any specific rules about the use of &quot;that&quot; in the sentences I reported as example? Hero who is against enhancements but has some himself libpng problems for QGIS I'm using ubuntu 18.04 and if I download QGIS 2.18 and I try to run it, I get this:  libpng warning: Application jmp_buf size changed Segmentation fault (core dumped)   If I try with QGIS 3.2, the error is:   libpng warning: Application was compiled with png.h from libpng-1.6.34 libpng warning: Application  is  running with png.c from libpng-1.2.56 libpng error: Incompatible libpng version in application and library   So it's clear that the problem is with libpng.   I purged libpng-dev and reinstall again but nothing changed.   I tried to purge libpng16-16 but I get:  sudo apt purge libpng16-16 Reading package lists... Done Building dependency tree        Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation:  The following packages have unmet dependencies:  libgdk-pixbuf2.0-0 : Depends: libpng16-16 (&gt;= 1.6.2-1) but it is not going to be installed                       Recommends: libgdk-pixbuf2.0-bin  libgtk-3-0 : Depends: libcairo-gobject2 (&gt;= 1.10.0) but it is not going to be installed               Depends: libcairo2 (&gt;= 1.14.0) but it is not going to be installed               Depends: libfontconfig1 (&gt;= 2.12) but it is not going to be installed               Depends: libpango-1.0-0 (&gt;= 1.40.5) but it is not going to be installed               Depends: libpangocairo-1.0-0 (&gt;= 1.40.5) but it is not going to be installed               Depends: libpangoft2-1.0-0 (&gt;= 1.40.5) but it is not going to be installed               Depends: adwaita-icon-theme               Recommends: libgtk-3-bin E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.   and then:  ~$ sudo apt install libgdk-pixbuf2.0-bin libgtk-3-bin Reading package lists... Done Building dependency tree        Reading state information... Done libgdk-pixbuf2.0-bin is already the newest version (2.36.11-2). libgtk-3-bin is already the newest version (3.22.30-1ubuntu1). 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. ~$ sudo apt install libgtk-3-0 libgdk-pixbuf2.0-0 Reading package lists... Done Building dependency tree        Reading state information... Done libgdk-pixbuf2.0-0 is already the newest version (2.36.11-2). libgtk-3-0 is already the newest version (3.22.30-1ubuntu1). 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.   At this point I'm afraid of breaking something if I continue trying things, so I come here for advice before.  I deleted and reinstalled ubuntu. I installed first thing qgis and it was working. Afterwards I compiled gdal, from source to have it from python as stand alone. It might be this, but I had done this previously without any problems. 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