Bug 170827 ControlDecoration uses the wrong GC method to render text
The constructor of the Hover in ControlDecoration: hoverShell.addPaintListener(new PaintListener() { public void paintControl(PaintEvent pe) { pe.gc.drawString(text, hm, hm); if (!CARBON) { pe.gc.drawPolygon(getPolygon(true)); } } }); The size of the hover is correctly performed when there are carriage returns in the text. However, the text is painted as String. This causes only the first line to be painted and the rest of the hover is empty. The fix is to use GC.drawText' instead.
bundles/org.eclipse.jface/src/org/eclipse/jface/fieldassist/ControlDecoration.java
pe.gc.drawString(text, hm, hm);
					if (!CARBON) {
						pe.gc.drawPolygon(getPolygon(true));
					}
				}
			});
			hoverShell.addMouseListener(new MouseAdapter() {
				public void mouseDown(MouseEvent e) {
					hideHover();
				}
			});
		}
		/*
		 * Compute a polygon that represents a hover with an arrow pointer. If
		 * border is true, compute the polygon inset by 1-pixel border. Consult
		 * the arrowOnLeft flag to determine which side the arrow is on.
		 */
		int[] getPolygon(boolean border) {
			Point e = getExtent();
			int b = border ? 1 : 0;
			if (arrowOnLeft) {
				return new int[] { 0, 0, e.x - b, 0, e.x - b, e.y - b,
						hao + haw, e.y - b, hao + haw / 2, e.y + hah - b, hao,
						e.y - b, 0, e.y - b, 0, 0 };
			}
			return new int[] { 0, 0, e.x - b, 0, e.x - b, e.y - b,
					e.x - hao - b, e.y - b, e.x - hao - haw / 2, e.y + hah - b,
					e.x - hao - haw, e.y - b, 0, e.y - b, 0, 0 };
		}
		/*