title: GWT - Unexpected scrollbar appeared in GWT-DataGrid while using Canvas
body: <p>I found a bug that there will be some unexpected scrollbars appeared in GWT-DataGrid when using Canvas in the same area. No matter what functions of Canvas I used, even if I just use Canvas to draw a line, it will cause problem. The scenario is hard to describe clearly. I will try my best. Hope you know what I am talking about. </p>
  
  <p>In my app, when users click a button, the popup panel which contains a DataGrid will show up. Under the popup panel, in RootLayoutPanel, I have a Canvas which draws some graphs. If Canvas and the DataGrid appeared in the same area (they "interlace"), the bug will appear (some unexpected weird scroll bars show up). On the other hand, if they don't appear in the same area, or I just do not let the Canvas start drawing if they interlace, then no problem at all. For example, if I move the Canvas away from underneath of popup panel which contains DataGrid,so that they do not interlace, DataGrid will have no problem.</p>
  
  <p><img src="https://i.stack.imgur.com/ND9eB.png" alt="bugs appear"></p>
  
  <p><img src="https://i.stack.imgur.com/CIcaQ.png" alt="no bugs appeared">
  I found someone have reported this bug in Google as well. And it is exactly what I encounter. But no one can answer why or provide some workaround.
  <a href="http://code.google.com/p/google-web-toolkit/issues/detail?id=7338" rel="nofollow noreferrer">http://code.google.com/p/google-web-toolkit/issues/detail?id=7338</a></p>
  
  <p>If you have any workaround. please let me know. Thanks</p>