Use customized `PanelLayout#removeWidget` and
`PanelLayout#insertWidget` logic for the layout
updates. The customized functions ensure no side
effect if adding/removing the widget to/from the
layout but it's already present/absent.
Unlike the default [`PanelLayout#removeWidget`](9f5e11025b/packages/widgets/src/panellayout.ts (L154-L156))
behavior, do not try to remove the widget if it's
not present (has a negative index). Otherwise,
required widgets might be removed based on the
default [`ArrayExt#removeAt`](9f5e11025b/packages/algorithm/src/array.ts (L1075-L1077))
behavior.
Closes: arduino/arduino-ide#2354
Signed-off-by: Akos Kitta <a.kitta@arduino.cc>
- update Theia to `1.39.0`,
- remove the application packager and fix the security vulnerabilities,
- bundle the backed application with `webpack`, and
- enhance the developer docs.
Co-authored-by: Akos Kitta <a.kitta@arduino.cc>
Co-authored-by: per1234 <accounts@perglass.com>
Signed-off-by: Akos Kitta <a.kitta@arduino.cc>
