H5P Course Presentation: Background becomes too dark when opening text button / background opacity setting has no effect

Description

The H5P Course Presentation content type behaves incorrectly, or differently than before, when viewing explanatory texts that are opened via buttons.

When a text element configured as a button is clicked, the slide background is darkened so strongly that the background image is no longer visible. This is problematic for scenarios where the explanatory text intentionally refers to elements in the image behind it.

Currently, it does not seem possible to adjust this behavior. The “Background opacity” setting for the text element and/or background image does not appear to have any visible effect. In tests with the values 25 and 100, the result was the same: the background became very dark, almost completely blacked out.

If there is no functional setting to control the strength of the background overlay/masking, existing H5P Course Presentation content may need to be redesigned conceptually or transferred to another content format.

Observation / Comparison with Existing Content

H5P Course Presentation content created before the change still appears as expected: when an info text embedded via a button is opened, the background remains sufficiently visible and only slightly darkened.

Steps to Reproduce

1. Open the content bank/content storage in a course.
2. Create a new H5P Course Presentation.
3. Add a slide with a full-slide image as the background.
4. Place a text element on the slide.
5. Configure the text element to be displayed as a button.
6. Save the content.
7. Open/view the saved content.
8. Click the text button so that the explanatory text is displayed.
9. Optional: Edit the text element and change the “Background opacity” setting, e.g. to 25 or 100, save again, and retest.

Expected Behavior

When clicking the text button, the explanatory text should be displayed while the background image remains visible.

The background may be slightly darkened, but it should still be sufficiently recognizable so that the explanatory text can refer to specific elements in the image.

The “Background opacity” setting should visibly affect the appearance.

Actual Behavior

When the text button is clicked, the background is darkened so strongly that the image is no longer recognizable.

As a result, the explanatory text can no longer meaningfully refer to the image behind it.

The “Background opacity” setting appears to have no effect. In tests with the values 25 and 100, the appearance remained unchanged: the background was very dark or almost completely blacked out in both cases.