Adjust selection bounds for CTabRenderring

Selected tabs highlight look slightly off and more noticeable when zoom
is not 100%. These adjusted value shows no gaps from top and better
aligned highlights for tabs (Theme is enabled)

Author: ShahzaibIbrahim

bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/CTabRendering.java

@@ -627,10 +627,11 @@ void drawSelectedTab(int itemIndex, GC gc, Rectangle bounds) {
 				highlightOnTop = !highlightOnTop;
 			}
 			int highlightHeight = 2;
-			int verticalOffset = highlightOnTop ? 0 : bounds.height - (highlightHeight - 1);
+			int verticalOffset = highlightOnTop ? 0 : outlineBoundsForOutline.height - (highlightHeight - 1);
 			int horizontalOffset = itemIndex == 0 || cornerSize == SQUARE_CORNER ? 0 : 1;
 			int widthAdjustment = cornerSize == SQUARE_CORNER ? 0 : 1;
-			gc.fillRectangle(bounds.x + horizontalOffset, bounds.y + verticalOffset, bounds.width - widthAdjustment,
+			gc.fillRectangle(outlineBoundsForOutline.x + horizontalOffset, outlineBoundsForOutline.y + verticalOffset,
+					outlineBoundsForOutline.width - widthAdjustment,
 					highlightHeight);
 		}