When two or more web parts are added to the standard view page then the drop down menu for choosing view gets disappeared.
Resolution that worked for me is to edit the view Page in the SharePoint Designer advanced Mode
Look for the line,
<SharePoint:ListTitleViewSelectorMenu AlignToParent="true" id="LTViewSelectorMenu" runat="server" />
and replace with,
<SPAN id=onetidPageTitleSeparator><SPAN><SPAN style="POSITION: relative; WIDTH: 11px; DISPLAY: inline-block; HEIGHT: 11px; OVERFLOW: hidden"><IMG style="POSITION: absolute; BORDER-RIGHT-WIDTH: 0px; BORDER-TOP-WIDTH: 0px; BORDER-BOTTOM-WIDTH: 0px; BORDER-LEFT-WIDTH: 0px; TOP: -585px !important; LEFT: 0px !important" alt=: src="/_layouts/images/fgimg.png"></SPAN></SPAN></SPAN>
<SharePoint:ViewSelectorMenu ID="viewSelectorMenu1" runat="server" />
Hope it helps someone !!