In theory, is adding the property flickable: theIDofTheFlickableElement here:
https://github.com/ubports/morph-browser/blob/xenial/src/app/webbrowser/BrowserPage.qml#L43

The QtWebEngine has a property "scrollPosition" where we can watch at scrollPosition.y to determine if the user has scrolled down to hide the navigation bar: https://doc.qt.io/qt-5/qml-qtwebengine-webengineview.html#scrollPosition-prop

that would help a lot to see the full screen, but that would be necessary also in the webapps, because by default there is a space that is not seen of the web page in its inferior zone, the web page is not complete, you can try for example with My Ut forum

Could you add a screenshot @josele13 ?

Yes of course...
One of the photos is Morph, the other is the webapp, both down the page to the maximum possible. The webapp does not open the whole page, the space occupied by the top bar,

greetings...

The webbrowser-app did have the feature, that when scrolling down a website, the navigation bar scrolled out of view upwards.
Therefore more space for the content was available.
When scrolling up, the header bar scrolled back into view.
We could try to reimplement that at some point.

Hello,
Balcy, any news regarding this feature?
It would be really important to have this implemented in terms of usability.
Thank you in advance for your hard work

The last time I tried that it just caused much flickering, because I changed the browser size during scroll.
Then I saw there is already a ScrollTracker from the old webbrowser app, that needed to be adapted to morph.
Changes:
xenial_-_pdfextension...xenial_-_scrollchrome

The branch https://github.com/ubports/morph-browser/compare/xenial_-_scrollchrome is based on the the PR for QtWebEngine 5.14, the change itself should work for Qt 5.11 as well