Fix output highlighting for non-classic themes

[sergio-calvo-devo]

The text highlighting has some problems with themes other than the classic one. There are two overlapping texts and the result is illegible.

[CLAassistant]

All committers have signed the CLA.

[d98762625]

Hello, thanks a lot for your PR.

I have been able to replicate this issue and can confirm that your PR stops the additional text from being show when you disable the to base64 operation. For the record I took these steps:

• add To Base64 operation
• add some input text
• highlight some of the input text (which also highlights some output chars)
• disable the operation
• see the overlapping text

When trying out your change, I can see that the "old" output is not visible, but the highlight it still highlighting where the "old" characters should be. This changes when you move the cursor off the operation panel in the UI (just like how the original issue resolves itself if you unfocus)

I think this new behaviour is more dangerous than the original, because the highlight looks OK, but it is not what should be highlighted.

To approve this, I would like to see the actual highlight be updated upon pressing the 'disable' button on the To Base64 operation

[a3957273]

The previous comments on this PR haven't been resolved and we're now 4 years on, so I'm going to close this ticket as stale. If you have time in the future to update this, feel free to open a new PR :)