**Khelpcenter menu does not work (some parts of TreeView not expanded)**
Package: khelpcenter version 5.7.3
KDE Frameworks Version 5.51.0
Qt Version 5.11.1
KDE Plasma Version 5.13.90
Kernel Version 4.15.0-34-generic
OS Type: 64-bit
NAME="KDE neon"
VERSION="Developer Edition"
ID=neon
ID_LIKE="ubuntu debian"
PRETTY_NAME="KDE neon Developer Edition"
VERSION_ID="18.04"
HOME_URL="http://neon.kde.org/"
SUPPORT_URL="http://neon.kde.org/"
BUG_REPORT_URL="http://bugs.kde.org/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic
On 2018.09.26, an upgrade was made by command dist-upgrade.
Incorrect to works the contents index tree on left half of application window (TreeWidget) khelpcenter.
STEPS TO REPRODUCE BUG
0. Open «System Settings» (systemsettings5) → Input Devices → Mouse → General → Choose «Double-click to open files and folders» (!!!)
1. Start khelpcenter (in any way).
2. Choose menu item - "Kinfocenter Modules" - in the left half of the application window.
3. Items not expand.
OBSERVED RESULT
0. User uses - Double-click to open files and folders.
1. Pressing some of the menu items does not produce any results (the corresponding help information is not displayed in the right half of the application window).
(Open khelpcenter → choose «KinfoCenter Modules» - items not expand )
EXPECTED RESULT
Menu should work correctly:
- all menu items should be displayed,
- subparagraphs should open and disclose subtrees,
- the corresponding help is displayed in the right half of the application window.