PDF Viewer: utility panel visible event if component property set to False

my utilityPaneVisible property is set to False but if i change the PDF path (using a dropdown or whatever) the utility panel comes out again.
i tried to print out the event.propertyName changing in the PDF component but no properties changing.

Is it a bug or it's supposed to shows every time you change PDF? The guide doesn't say anything about it.

Attached to this post, the pic of the sidebar that i want to hide/remove for EVERY file.



PDF contain instructions on what general UI components of common viewers are supposed to show at startup. You might want to examine the PDF itself more closely, or tweak the tools that are producing them for you.