[TIMOB-2788] leftNavButton flashes within a navigation group

Same problem with Tab Group. The leftNavButton flashes every time you select the tab. This does not happen to the rightNavButton or the Tool bar buttons.

   
   // Create the logout button
   btnHome = Titanium.UI.createButton({
       image:ICON_HOME,
       width:40, 
       style:Titanium.UI.iPhone.SystemButtonStyle.PLAIN
   });
   win1.leftNavButton = btnHome;
   btnHome.addEventListener('click', function() { /* do something */ });
   

Just noticed that the leftNavButton is smaller than the rightNavButton even though they both have their width set the same. Clue?

   
       // Create the home button
       btnHome = Titanium.UI.createButton({
           image:ICON_HOME,
           width:40, 
           style:Titanium.UI.iPhone.SystemButtonStyle.PLAIN
       });
       win1.leftNavButton = btnHome;
       btnHome.addEventListener('click', function() { browser_home(); });
           
       // Create the refresh button
       btnRefresh = Titanium.UI.createButton({
           image:ICON_REFRESH,
           width:40, 
           style:Titanium.UI.iPhone.SystemButtonStyle.PLAIN
       });
       win1.rightNavButton = btnRefresh;
       btnRefresh.addEventListener('click', function() { browser_refresh(); });