Issue: Missing "Apps you can add" in SharePoint 2013

I have created new master page using html everything working as expected and deployed on production. But after some time user found that they are not able to add custom apps on SharePoint portal.

After searching on this we game to know that we missed two important tags in the master page.

<asp:ContentPlaceHolder id="PlaceHolderPageTitleInTitleArea" runat="server"/>
<asp:ContentPlaceHolder id="PlaceHolderLeftNavBar" runat="server" />

if preview giving any error like 'asp' is not valid or something then add as below

   <!--MS:<asp:ContentPlaceHolder id="PlaceHolderPageTitleInTitleArea" runat="server">-->
            <!--ME:</asp:ContentPlaceHolder>-->

NOTE: Some times you might commented this code by mistake without knowing.

I have added these two tags back to the master page then "Apps you can add" section came back.