Comment # 3 on bug 1188074 from Jazz Fan

I have found this <https://bugs.kde.org/show_bug.cgi?id=430036> bug report
which seems related. After reading that I was able to at least remove the main
toolbar permanently by deleting the entry

<ToolBar name="mainToolBar">
  <text>Main Toolbar</text>
  <index>0</index>
  <Action name="new-tab"/>
  <Action name="split-view-left-right"/>
  <Action name="split-view-top-bottom"/>
</ToolBar>

in my ~/.local/share/kxmlgui5/konsole/konsoleui.rc file. However, the session
toolbar doesn't seem to be mentioned in that file.