[Gambas-bugtracker] Bug #2835: Strange Cursor in the Combobox

[bugtracker at gambaswiki.org]

http://gambaswiki.org/bugtracker/edit?object=BUG.2835&from=L21haW4-

Claus DIETRICH reported a new bug.

Summary
-------

Strange Cursor in the Combobox

Type             : Bug
Priority         : Medium
Gambas version   : Unknown
Product          : Unknown


Description
-----------

In an application I suddenly recognized a strange cursor when moving with the mouse through the item list. This happened after I extended the number of list items so that the scroll slider appeared on the right side of the list.
I replicated this part of the app in a very small demo (attached) and found, that it also happens there - unfortunately with a lower reliability but noticeable and very annoying in a real app.

Please take note that following factors seem to have an impact on the occurrence of the bug:
- The combo is set to Read-Only (!)
- The number of items is so big that the vertical scroll slider appears
- The mouse cursor is moved from the Combo-pad directly to the vertical scroll-slider (!)
- It seems that it happens more often, when the combo is part of a bigger app - meaning that time effect may be relevant. 

I am not sure, whether this doesn't happen with GTK3, but in a short test with GTK3 I couldn't provoke the bug.
 
With best regards
Claus


System information
------------------

[System]
Gambas=3.18.4
OperatingSystem=Linux
Distribution=Linux Mint 20.3 Una
Kernel=5.4.0-166-generic
Architecture=x86_64
Cores=4
Memory=7821M
Language=de_DE.UTF-8
Desktop=CINNAMON
DesktopResolution=96
DesktopScale=7
WidgetTheme=mint-x
Font=Ubuntu,10

[Programs]
gcc=gcc (Ubuntu 9.4.0-1ubuntu1~20.04.2) 9.4.0

[Libraries]
Cairo=libcairo.so.2.11600.0
Curl=libcurl.so.4.6.0
DBus=libdbus-1.so.3.19.11
GDK2=libgdk-x11-2.0.so.0.2400.32
GDK3=libgdk-3.so.0.2404.16
GStreamer=libgstreamer-1.0.so.0.1603.0
GTK+2=libgtk-x11-2.0.so.0.2400.32
GTK+3=libgtk-3.so.0.2404.16
OpenGL=libGL.so.1.7.0
Poppler=libpoppler.so.97.0.0
QT5=libQt5Core.so.5.12.8
RSvg=librsvg-2.so.2.47.0
SDL=libSDL2-2.0.so.0.10.0
SQLite 3=libsqlite3.so.0.8.6

[Environment]
CINNAMON_VERSION=5.2.7
DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
DESKTOP_SESSION=cinnamon
DISPLAY=:0
GB_GUI=gb.gtk3
GDMSESSION=cinnamon
GDM_LANG=de_DE
GIO_LAUNCHED_DESKTOP_FILE=/usr/share/applications/gambas3.desktop
GIO_LAUNCHED_DESKTOP_FILE_PID=312854
GJS_DEBUG_OUTPUT=stderr
GJS_DEBUG_TOPICS=JS ERROR;JS LOG
GNOME_DESKTOP_SESSION_ID=this-is-deprecated
GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
GTK3_MODULES=xapp-gtk3-module
GTK_MODULES=gail:atk-bridge
GTK_OVERLAY_SCROLLING=1
HOME=<home>
LANG=de_DE.UTF-8
LANGUAGE=de_DE.UTF-8
LC_ADDRESS=de_DE.UTF-8
LC_ALL=de_DE.UTF-8
LC_IDENTIFICATION=de_DE.UTF-8
LC_MEASUREMENT=de_DE.UTF-8
LC_MONETARY=de_DE.UTF-8
LC_NAME=de_DE.UTF-8
LC_NUMERIC=de_DE.UTF-8
LC_PAPER=de_DE.UTF-8
LC_TELEPHONE=de_DE.UTF-8
LC_TIME=de_DE.UTF-8
LOGNAME=<user>
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
PWD=<home>
QT_ACCESSIBILITY=1
QT_LOGGING_RULES=*.debug=false
QT_QPA_PLATFORMTHEME=qt5ct
SESSION_MANAGER=local/<hostname>:@/tmp/.ICE-unix/1256,unix/<hostname>:/tmp/.ICE-unix/1256
SHELL=/bin/bash
SHLVL=0
SSH_AGENT_PID=1329
SSH_AUTH_SOCK=/run/user/1000/keyring/ssh
TZ=:/etc/localtime
USER=<user>
XAUTHORITY=<home>/.Xauthority
XDG_CONFIG_DIRS=/etc/xdg/xdg-cinnamon:/etc/xdg
XDG_CURRENT_DESKTOP=X-Cinnamon
XDG_DATA_DIRS=/usr/share/cinnamon:/usr/share/gnome:<home>/.local/share/flatpak/exports/share:/var/lib/flatpak/exports/share:/usr/local/share:/usr/share
XDG_GREETER_DATA_DIR=/var/lib/lightdm-data/<user>
XDG_RUNTIME_DIR=/run/user/1000
XDG_SEAT=seat0
XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
XDG_SESSION_CLASS=user
XDG_SESSION_DESKTOP=cinnamon
XDG_SESSION_ID=c2
XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session0
XDG_SESSION_TYPE=x11
XDG_VTNR=7