I have already submitted this issue through Opera's built-in Report a problem feature:

BUG-27619
https://opera.atlassian.net/servicedesk/customer/portal/52/BUG-27619

Steps to reproduce

1. Open any webpage in Opera.
2. Open DevTools with Ctrl+Shift+I and dock it to the right side.
3. Click a link to navigate to another page in the same tab.
4. Observe the new page while DevTools is still open.

Actual result

The new page is rendered using the full browser window width, as if DevTools were not docked. DevTools then covers the right part of the page.

For example, window.innerWidth on the newly loaded page reports the full browser content width instead of the width available to the page after accounting for the docked DevTools.

If I manually resize the DevTools panel or resize the browser window, the viewport is recalculated and the page immediately adjusts to the correct width.

Expected result

When navigating to a new page with DevTools already docked, the new page should immediately receive the correct viewport size, excluding the area occupied by DevTools.

Comparison with Chrome

The same scenario works correctly in Google Chrome. After navigation, the page is automatically resized to the available area next to the docked DevTools.

This appears to be a regression/bug in Opera's handling of the page viewport during navigation with docked DevTools.

A similar issue has previously been reported as BS-92008.

Please investigate whether the viewport dimensions are being initialized before Opera applies the docked DevTools layout.

System information

• Opera: 133.0.5932.85
• OS: Windows 10 (10.0.19045)
• CPU: Intel(R) Core(TM) i7-4790K CPU @ 4.00 GHz
• GPU: NVIDIA GeForce GTX 960
• Country: Estonia