最近同事的项目中，
打开一个页面的时候，发现
The maximum number of Web Parts for all zones on this page has been exceeded.
如此信息，使用SPD打开页面的时候，发现同一WebPart重复10多次，
那么一个页面可以有多少个Web Part呢？
The limit is customizable in web.config file,
50 (default) - http://technet.microsoft.com/en-us/library/cc262787.aspx
100 (recommended max) - http://technet.microsoft.com/en-us/library/cc287743.aspx
最终的原因参考
http://vivek-soni.blogspot.com/2010/08/duplicate-web-parts-shown-in-sharepoint.html
Issue:
Using the same
web part zone GUID multiple times whether in same page layout or a different
page layout would result into the web part being shown up multiple times.
Resolution:
Ensure that
every web part zone and web part in your page layouts have a unique GUID across
your site collection.