The fix for #1210 breaks image styling on intro pages

[wiresketch]

As stated in the title, version 4.30 of Eclipse has no images on intro pages. This was broken by the fix for #1210 which removes the blank.gif image. The css styling uses this image element to show the actual image using code like this:

a#pde img { background-image : url(../../images/topiclabel/ov_eclplugindev48.svg); }
a#pde:hover img { background-image : url(../../images/topiclabel/ov_eclplugindev48.svg); }

Since the image element is missing now, now images are displayed.

Here's what the Eclipse SDK 4.29's Welcome Page looked like:

Here's what the Eclipse SDK 4.30's Welcome Page looked like now:

[BeckerWdf]

@wiresketch: Do you have an idea how to fix the issue #1210 without causing this regression?

[wiresketch]

@BeckerWdf Sorry, I don't have a good handle on this code. I've just noticed the problem and tried to identify the commit that caused it.

[wiresketch]

@BeckerWdf Perhaps a better place to fix this would be in the CSS that styles those pages. Since those pages are HTML it makes sense to debug them in a browser. There is no obvious way to do it, but what I did to investigate this issue was to put a breakpoint in BrowserIntroPartImplementation#generateContentForPage, extract the generated HTML content using the debug view, put it in a html file and then open it in a browser. Since all resource references are absolute, this works and you can play with CSS styling and see where the original padding issue comes from.

[wiresketch]

Looking more into it, it looks like the change must be made in this file:
https://github.com/eclipse-platform/eclipse.platform/blob/master/ua/org.eclipse.ui.intro.universal/themes/solstice/html/root.css

Specifically line 210 this style:

#page-links a#workbench,
#action-links a#workbench {
    position : absolute;
    right : 20px;
    top : 5px;
    width : auto;
    text-align:center;
    margin-bottom : 0px;
}

Removing the top margin of 5px improves things.

What I've noticed is that the page looks fine in quirks mode (no DOCTYPE). The DOCTYPE generation is controlled by a theme property. Specifically for soltice this was enabled in this commit 7 years ago: eclipse-platform/eclipse.platform@13c830c . Perhaps it went unnoticed that the DOCTYPE change influences the rendering.

[BeckerWdf]

What I've noticed is that the page looks fine in quirks mode (no DOCTYPE). The DOCTYPE generation is controlled by a theme property. Specifically for soltice this was enabled in this commit 7 years ago: eclipse-platform/eclipse.platform@13c830c . Perhaps it went unnoticed that the DOCTYPE change influences the rendering.

Yes. I also notices this while doing the initial fix.

[BeckerWdf]

@wiresketch: Thanks for your hints.
I have created a PR that should not correctly address this issue. See: eclipse-platform/eclipse.platform#1025

Do you have the possibility to manually test with my PR?

[BeckerWdf]

This is fixed with the above PR.