lubuntu 19.04 pcmanfm-qt crashes 'trap divide error' on monitor-change-position

Lubuntu 19.04 QA-test [Live environment on daily-ISO]

I've been having trouble with pcmanfm-qt moving around the 2nd display (other bug-reports) and thus I've been adjusting the position of the screens (relative to each other) to see if monitor-position effects the jumping-window-on-select of device/folder/.. in pcmanfm-qt.

On some of these display or monitor-settings-adjustments the open windows of pcmanfm-qt has crashed/closed.

dmesg shows

[ 25.954105] e1000e: eno1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: Rx/Tx
[ 25.954145] IPv6: ADDRCONF(NETDEV_CHANGE): eno1: link becomes ready
[ 29.321110] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 29.321112] Bluetooth: BNEP filters: protocol multicast
[ 29.321116] Bluetooth: BNEP socket layer initialized
[ 320.898561] traps: pcmanfm-qt[1721] trap divide error ip:56068da67ff3 sp:7ffef1f5c190 error:0 in pcmanfm-qt[56068da34000+4e000]
[ 846.384160] FS-Cache: Loaded
[ 846.411323] RPC: Registered named UNIX socket transport module.
[ 846.411324] RPC: Registered udp transport module.
[ 846.411324] RPC: Registered tcp transport module.
[ 846.411325] RPC: Registered tcp NFSv4.1 backchannel transport module.
[ 846.441412] FS-Cache: Netfs 'nfs' registered for caching
[ 1224.928345] NFS: Registering the id_resolver key type
[ 1224.928352] Key type id_resolver registered
[ 1224.928352] Key type id_legacy registered
[ 9648.386219] traps: pcmanfm-qt[2099] trap divide error ip:562c62897ff3 sp:7ffea1f55ff0 error:0 in pcmanfm-qt[562c62864000+4e000]
[10717.478009] traps: pcmanfm-qt[6631] trap divide error ip:558fde12aff3 sp:7ffe28f8a850 error:0 in pcmanfm-qt[558fde0f7000+4e000]

The `dmesg` report snipped shows 3 crashes.

The significance is not great, the user (me) just re-opens pcmanfm-qt, and no-one adjusts their screen-positions very often, and that is the only time it crashed - so importance is low.

Possibly related (why I'm adjusting screen position) is 1804329m 1810079. 1812342 which are all problems I've had today with pcmanfm-qt (causing me to change screen positioning & thus come across these crashes).

lubuntu@lubuntu:~$ ls -lha /var/crash/
total 11M
drwxrwsrwt 1 root whoopsie 80 Jan 18 06:55 .
drwxr-xr-x 1 root root 160 Jan 17 16:44 ..
-rwxrwxrwx 1 root whoopsie 0 Jan 18 06:55 .lock
-rw-r----- 1 lubuntu whoopsie 11M Jan 18 06:55 _usr_bin_pcmanfm-qt.999.crash

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: pcmanfm-qt 0.13.0-2ubuntu2
ProcVersionSignature: Ubuntu 4.18.0-11.12-generic 4.18.12
Uname: Linux 4.18.0-11-generic x86_64
ApportVersion: 2.20.10-0ubuntu18
Architecture: amd64
CasperVersion: 1.401
CurrentDesktop: LXQt
Date: Fri Jan 18 09:51:59 2019
LiveMediaBuild: Lubuntu 19.04 "Disco Dingo" - Alpha amd64 (20190117)
SourcePackage: pcmanfm-qt
UpgradeStatus: No upgrade log present (probably fresh install)

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More information may be found in https://bugs.launchpad.net/ubuntu/+source/pcmanfm-qt/+bug/1812372

To ensure the crash report got uploaded from that bug-report

I went into /var/crash & `ubuntu-bug _usr<tab>` the report.

In filing of 1812369 I only `ubuntu-bug pcmanfm-qt` as I knew it was crashing from `dmesg` and behavior (it'd close). Rather than abort the reporting, I decided I'd run what created this to ensure it was uploaded.
Info in 1812372 was from the second ubuntu-bug filing...