[Gui] QSint: fix QGroupBox visibility

[donovaly]

• fixes qwindowsvistastyle.dll does not style the line color #6102
• the point is that we don't set any style for the group boxes, therefore the windows style steps as nothing was set yet. Its default style is the color #dddddd which is hardly visible on our blue default style.
  as solution set an explicit color and use the grooved style.

This is the result:

[berndhahnebach]

for feature branch PR_7292. Pipeline 601196151 was triggered at 10066dc. All CI branches and pipelines.

[berndhahnebach]

for feature branch PR_7292. Pipeline 601204606 was triggered at b62e9d0. All CI branches and pipelines.

[Roy-043]

Thanks for working on this, and fixing the true cause of the issue.

[donovaly]

@Roy-043 , I am a bit reluctant about the border color. What is in your opinion better?:

(left is #bbbbbb, right ist #cccccc)

[luzpaz]

@donovaly should we let the FreeCAD theme-ers know about this ? (ie FreeCAD/FreeCAD-addons#201)

[donovaly]

@donovaly should we let the FreeCAD theme-ers know about this ? (ie FreeCAD/FreeCAD-addons#201)

This is not necessary since the various themes use their own style. The fix here is only for the default style - meaning when no style file is applied.

What is your opinion, better the left or right image?

[luzpaz]

Right side.

[Roy-043]

I prefer the left image. On the right the contrast is too low IMO.

[GeneGH]

I like the left one better, but modern style is to make everything gray on light gray on off-white on white. Very low constrast is the current fad. Great for teenagers; not so great for more "mature" folks.

[adrianinsaval]

Left has better contrast IMO, perhaps a blueish color would work better here?
Quick edit on gimp using #a09ebc

[luzpaz]

too bad the left/right tracks for Transparency and Line-Transparency aren't slightly shadowed. That color doesn't distiguish well from the widget background

[donovaly]

Thanks for the feedback.

I made a mistake here: for years nobody really cared and now I triggered a discussion about the right color for a box line. This is not really worth it.

@Roy-043 was insisting that the issue got fixed, so shall it be his choice: :-) -> merging the PR is it is.