OK. I had a thought. Started in Safe Mode - all is OK. So I then went around disabling all extensions and *as I disabled one* the window maximized width-wise. That extension is: CustomizeMyBird.
So I'll report the issue there instead. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to thunderbird in Ubuntu. https://bugs.launchpad.net/bugs/1801782 Title: Main window maximizes width on the closing appplication. Status in Mozilla Thunderbird: Confirmed Status in thunderbird package in Ubuntu: New Bug description: If I close thunderbird using File->Quit (or ctrl+Q) the window maximizes to the screen width just before it closes and retains that max-width on the next restart. This does not happen if I close thunderbird with the window-manager's Close button in the titlebar. (I don't normally run windows full-screen, as to me that rather removes the usefulness of having a window system.) ProblemType: Bug DistroRelease: Ubuntu 18.10 Package: thunderbird 1:60.2.1+build1-0ubuntu1 ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12 Uname: Linux 4.18.0-10-generic x86_64 AddonCompatCheckDisabled: False ApportVersion: 2.20.10-0ubuntu13 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: gml4410 2178 F.... pulseaudio /dev/snd/controlC1: gml4410 2178 F.... pulseaudio BuildID: 20181011091051 Channel: Unavailable CurrentDesktop: KDE Date: Mon Nov 5 19:55:37 2018 ForcedLayersAccel: False IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback IncompatibleExtensions: Lightning - {e2fda1a4-762b-4020-b5ad-a41df1933103} Microbird - {59EAEC94-299A-43E3-BBE4-090880139DAA} InstallationDate: Installed on 2017-11-01 (369 days ago) InstallationMedia: Kubuntu 17.10 "Artful Aardvark" - Release amd64 (20171017.1) IpRoute: default via 192.168.1.1 dev wlp2s0 proto dhcp metric 600 169.254.0.0/16 dev wlp2s0 scope link metric 1000 192.168.1.0/24 dev wlp2s0 proto kernel scope link src 192.168.1.10 metric 600 Plugins: Shockwave Flash - /usr/lib/flashplugin-installer/libflashplayer.so PrefSources: prefs.js Profiles: Profile0 (Default) - LastVersion=60.2.1/20181011091051 (In use) RunningIncompatibleAddons: True SourcePackage: thunderbird UpgradeStatus: Upgraded to cosmic on 2018-10-24 (12 days ago) dmi.bios.date: 07/29/2015 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 4.6.5 dmi.board.asset.tag: Tag 12345 dmi.board.name: W54_55SU1,SUW dmi.board.vendor: CLEVO dmi.board.version: Not Applicable dmi.chassis.asset.tag: No Asset Tag dmi.chassis.type: 9 dmi.chassis.vendor: Clevo dmi.chassis.version: N/A dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr4.6.5:bd07/29/2015:svnClevo:pnW54_55SU1,SUW:pvrNotApplicable:rvnCLEVO:rnW54_55SU1,SUW:rvrNotApplicable:cvnClevo:ct9:cvrN/A: dmi.product.family: Not Applicable dmi.product.name: W54_55SU1,SUW dmi.product.sku: Not Applicable dmi.product.version: Not Applicable dmi.sys.vendor: Clevo To manage notifications about this bug go to: https://bugs.launchpad.net/thunderbird/+bug/1801782/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp