, . @PeteBaughman, , ContextMenuStrip.Width - ( ContextMenuStrip.MaximumSize : (0,0)).
, , . : ContextMenuStrip.PerformLayout() .
( SuspendLayout ResumeLayout .)
: , ToolStripButton ContextMenuStrip, ToolStripMenuItem :
contextMenuStrip.Items.Add("Hello world");
PerformLayout() .