migration - Cannot reduce size of RCP view when migrated to Eclipse 4 -

i'm working on migrating set of eclipse rcp applications 3.6 4.2. i'm struggling issue rcp perspectives view height cannot reduced below size (looks 10% window height). code works fine in eclipse 3.x , user can reduce view height dragging border.

however, in 4.x height of top view (button view) can reduced upto value. can this, please?

public class perspective implements iperspectivefactory {      public static final string id = "im.rcptest2.fixedperspective";      public void createinitiallayout(ipagelayout layout) {         string editorarea = layout.geteditorarea();         layout.seteditorareavisible(false);          layout.addstandaloneview(buttonview.id, false, ipagelayout.top,                 0.1f, editorarea);          layout.addstandaloneview(view.id, false, ipagelayout.left,                 0.25f, editorarea);         ifolderlayout folder = layout.createfolder("messages", ipagelayout.top,                 0.5f, editorarea);         folder.addplaceholder(view2.id + ":*");         folder.addview(view2.id+":2");         folder.addview(view2.id+":3");          layout.getviewlayout(buttonview.id).setcloseable(false);          layout.getviewlayout(view.id).setcloseable(false);     }  }  public class buttonview extends viewpart  {     public buttonview() {     }      public static final string id = "im.rcptest2.buttonview"; //$non-nls-1$     private text text;       /**      * create contents of view part.      * @param parent      */     @override     public void createpartcontrol(composite parent) {         composite container = new composite(parent, swt.none);         container.setbackground(swtresourcemanager.getcolor(swt.color_gray));         container.setlayout(new gridlayout(2, false));         text = new text(container, swt.border);         text.setlayoutdata(new griddata(swt.fill, swt.top, true, false, 1, 1));         {             button btnmybutton = new button(container, swt.none);             btnmybutton.settext("mybutton");         }     }      @override     public void setfocus() {         // todo auto-generated method stub      }  } 

this looks value

int minsashpercent = 10; 

in org.eclipse.e4.ui.workbench.renderers.swt.sashlayout

there not seem way change value. thing write custom sash renderer class providing own renderer factory.