qss + QScrollBar background issue

Hi,

for QTextBrowsers I have defined "border-radius: 8px;". So I have to customize the scroll bars with transparent png's. But where the images are transparent there is still a other color which hides the border (-> see image).

I have set all entries in the QPallete to alpha = 0%, but there is still these color under the transparent image. How could I remove this color, to set the border visible?

Relevant qss-settings for the arrows:

Code:

---

QScrollBar::sub-line:vertical
  {
    background: rgba(255, 0, 0, 0%);
  }
QScrollBar::add-line:vertical
  {
    background: rgba(255, 0, 0, 100%);
  }

---

Thanks,
Lykurg.