GMap Block out of focus inside collapsed Collapsible Block and Javascript tools. Any idea why?

Hi,

I'm using Aquia Slate for building a Tour Operator website and I really would like to put the GMap Block into a collapsible block.

For achieving this, I've created a new block area (Preface Middle) and I'm using Collapsiblock 6.x-1.x-dev together with Javascript tools 6.x-1.0 and GMap 6.x-1.1-rc1.

Everything looks ok, until I'm setting the block collapse behavior to 'Collapsible, collapsed all the time' (that's what I want) or to 'Collapsible, collapsed by default'. Then, the Location map block is showing only partially, with the marker out of focus (see attached picture).

Just for checking, if I set it to 'Collapsible, expanded by default', then the map is showing without any problem, well centered with the marker in its middle.

I really don't know what to do to get it right. Is this about javascript (which I'm not really handling)? Has this more to do with the Gmap module ? (I have created an issue here: #781666). Has anyone succeed to display the Gmap Block into a collapsed-collapsible block, in a way or other?

Thanks very much for help!
.sahaj