outputChannel.show() no longer reveals output channel

[tetchel]

Description

outputChannel.show() no longer works. I believe this is a regression (see Theia versions below).

The output channel is created, but the Output view is not opened, and the channel is not brought to the front of the Output view. This means that calling show on an existing output channel has no effect.

Reproduction Steps

I've created a repository with a plugin (source and vsix) that you can reproduce with: https://github.com/tetchel/theia-output-show-bug

OS and Theia version:
I see the issue in Theia 0.15, 0.16, 0.16.1, and master branch.
I do NOT see the issue in theia 0.14, it works as expected.

Diagnostics:

I see this in the logs:
root WARN Widget was activated, but did not accept focus after 2000ms: outputView

[akosyakov]

@tetchel Could you check against #7570 please? The output view was completely reimplemented for better performance and user interactions.

[tetchel]

It is fixed in master 👍