Dev tools -> Template: copy to clipboard with "Ctrl-C" for "rendered" may include an undesired content

[ildar170975]

Checklist

• I have updated to the latest available Home Assistant version.
• I have cleared the cache of my browser.
• I have tried a different browser to see if it is related to my browser.
• I have tried reproducing the issue in safe mode to rule out problems with unsupported custom resources.

Describe the issue you are experiencing

Recent #23456, #24171 added a possibility to use "Ctrl-A" for a "rendered" pane to select a whole result which then may be copied with "Ctrl-C" to a clipboard.
But currently it may give different results:

Chrome 134.0.6998.36, MS Edge 133.0.3065.92:
the copied content includes data from the "edit" pane too (this is WRONG):

If the selected content is copied to a clipboard by a context menu ("Копировать" = "Copy"), then result is same WRONG:

FF 135.0.1:
the copied content only includes data from the "rendered" pane (this is OK):

Will see what I can do to fix this...
Any help is appreciated.

Describe the behavior you expected

as above

Steps to reproduce the issue

see above

What version of Home Assistant Core has the issue?

2025.3.0b4

What was the last working version of Home Assistant Core?

No response

In which browser are you experiencing the issue?

Chrome 134.0.6998.36, MS Edge 133.0.3065.92

Which operating system are you using to run this browser?

Win10x64

State of relevant entities

Problem-relevant frontend configuration

Javascript errors shown in your browser console/inspector

Additional information

No response