In Mesh Renderer component, information box for Scale in Lightmap parameter, namely "Object's size in lightmap has reached max atlas size." does not show up until the user hovers the mouse on inspector. Information box needs to be painted when user clicks on the object and inspector should display it when it's loaded.

Steps for reproduction:
1) Download the project below `ScaleInLightmapUIBug.zip`
2) Open the scene `t1`
3) Build the lighting
4) Click on the plane
5) Observe that information box is initially not painted
6) Hover the mouse on the inspector
7) Notice that information box shows up when user hovers the mouse on Mesh Renderer component

Notes:
- If steps are not clear, please see GIF attached below