On my website: http://www.bartvandermark.nl/

I changed in ATO the layout of the right sidebar and of the widgetcontainer. As a result on every page a grey dot appears just above the page title...

I have no idea what is causing the grey dot to appear. Can you give me some directions how to solve this?

Ok, I have figure something out: the widget container background was white. When i changed it to grey, the grey dot appeared. When I change the widget container background back to white, the grey dot is no longer visible.

Conclusion 1: the grey dot was there already, just not visible because it was white.
Conclusion 2: the color of the dot is affected by the background color of widget containers.
Conclusion 3: the form of the dot is caused by the corners of the widget container: when I remove the rounded corners of the widget container, the grey dot becomes a square...

I hope you can give me directions how to change this, i have no idea how to solve this...

Edit: I just adjusted the bottom-padding of the widget container from 4 to 10 and the strange dot is now als larger...

Why do you have a left sidebar that you have set to a width of 0 but have added a widget to?
if you don't want the left sidebar, just uncheck it in the sidebar options

.... feeling stupid....

Thanks for the quick reply, that was the solution