winforms designer behavior issue (tabs changed automatically, when trying put control on it)

VS 2010 I have simple win forms without code, just tab with 3 pages and buttons on each tabpage.

When i trying to put button on tabpage (on the left side of page it works fine, if i trying to put btn on right side of the page ...the designer will automatically change tabpage to another

Maybe problems is in this code

  this.tabControl1.SuspendLayout();
   this.WindowState = System.Windows.Forms.FormWindowState.Maximi开发者_如何学JAVAzed;
 this.groupBox8.ResumeLayout(false);
  this.groupBox8.PerformLayout();
   ((System.ComponentModel.ISupportInitialize)(this.dataGridView2)).EndInit();

P.S. When i delete all controls from one my tab(which always selected automatically) and designer work fine Later i delete rectangle controls(they are from Visual basic power pack and now designer works fine)

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Problem solved wheni deleted Visual Basic power pack rectangle controls from my page tab. This control have bug in vs 2010