Top stacklayout is not visible in UI when keyboard is on

My Xaml:

<StackLayout
   Orientation="Vertical">

       <StackLayout
          Orientation="Horizontal"> 
          //Group labels and back arrow
       </StackLayout>

       <ListView>
          //Message list
       </ListView>

       <Grid>
       //Plus symbol,Editor and send icon
       </Grid>

  </StackLayout> 

Screenshot:

Issue:

In normal screen there is a bar on the top(red circled). When click the editor on the bottom top bar is hiding. I need the top bar always on top. This issue is only in IOS part, in android this feature is working fine. How can I fix this issue?