Readonly mode missing Invert Background option in View menu

[sebastiaanveld]

Describe the Bug

Opening a document like a Visio .vsd file opens in read-only mode. In this mode there's the option for Dark Mode, that works, but there is no option for Invert Background so that could render a document hard to read or view. Would be nice to have the Invert Background option in the View menu just when optiong documents for editing.

When opening an editable document before a readonly document, which has set the background using the Invert Background option so the background is light while using Dark Mode and then ather this opening a readonly document then the background is Inverted automatically so the settings is remembered correctly. Just when hitting in the View menu Dark mode to disable it an then reable that tis will show the document background also dark as there is no Invert option in the menu.

Steps to Reproduce

1. Go to Nextcloud and open a readonly document like a Viso VSD or VSDX.
2. When COOL opens Click on View> Dark Mode so the view turns dark.
3. Notice the document background is also dark.
4. Open menu View, there's no option listed for Invert Background.

Expected Behavior

View menu should have a Invert Background option so a document background can be turned light again when usin Dark Mode.

Actual Behavior

Document may be hard to read and and view when the text and lines are dark in Dark Mode.

Screenshots

Desktop

(Please complete the following information)

OS: Windows 11 24H2, latest patches, x64 Dutch
Browser: Firefox
Version: 134.0.2, X64 Dutch

###CODE

COOLWSD version: 24.04.12.2(git hash: 875c3b0 (E))
LOKit version: Collabora Office 24.04.12.2(git hash: 7b59930)
Served by: openSUSE Leap 15.5
Server ID: 8b19fbf0
WOPI host:

Additional Context