We typically indicate the empty renderer in the page description file portal-object.xml. Not sure this approach will meet your needs.

<window>
 <window-name>Intro</window-name>
 <instance-ref>introInstance</instance-ref>
 <region>top</region>
 <height>2</height>
 <properties>
 <property>
 <name>theme.renderSetId</name>
 <value>emptyRenderer</value>
 </property>
 </properties>
 </window>

As for preventing drag & drop for windows within a specific region... we modified the dyna.js file to remove the drag & drop hooks for any window regions within an enclosing div which has a special class name we use to indicate the region shouldn't allow drag or drop activity. We add the special class name to a region in the layout JSP.

Maybe others have a better solution?

 

2) Is it possible to prevent the drag and drop functionalities in left region only ?.

I achived this by modifying renderHeader of DynaRegionRenderer.java

Region for which DnD to be disabled, region name will contain "NonDnD".

if (options.isDnDEnabled())
 {
 List win =(List)rrc.getWindows();
 boolean isDnD=false;
 Iterator it=win.iterator();
 while(it.hasNext())
 {

 WindowContext po=(WindowContext)it.next();
 if(po.getRegionName().indexOf("NonDnD")==-1)
 {
 markup.print("<div class=\"dnd-region\" id=\"");
 markup.print(rrc.getId());
 markup.print("\">");
 }
 Map mapObj=po.getProperties();




 }
// markup.print("<div class=\"dnd-region\" id=\"");
// markup.print(rrc.getId());
// markup.print("\">");
 }
 }
 else
 {
 delegate.renderHeader(rendererContext, rrc);
 }