button not firing in Firefox but fine in IE

Clicking on the button in FF does not have any effect except frustration but fine in IE, sounds like a bug?
<asp:Button ID="Button7" runat="server" Text="Query"
            onclick="Button7_Click" />
 
 protected void Button7_Click(object sender, EventArgs e)
    {  // Query
        Panel1.Visible = true;
        Panel2.Visible = false;
           GridView1.Visible = false;
      }
...