Unable to edit web part in a page

One of my business user added the page in site pages and included web part in it

And tried to edit the web-part , But I found no luck in getting the options

  

Solution:

1. Open Internet Explorer, select the Tools button , and then select Compatibility View settings.
2. Under Add this website, enter the URL of the site you want to add to the list, and then select Add  

                                                           or

Else it should be Microsoft Product issue

Set the co-authoring Limit for Web-application

Add-PSSnapin Microsoft.SharePoint.PowerShell
$site = Get-SPSite -Identity https://yourwebapplicationURL        
$site.Url
$site.WebApplication.WebService.CoauthoringMaxAuthors=19
$site.WebApplication.WebService.Update()
$site.Dispose()
Write-Host $site.WebApplication.WebService.CoauthoringMaxAuthors

The main purpose of the co-authoring is to limit the users for editing the particular document in document library .If the document is editing by too many users then users looses the UI experiance instantly ,So we limit the users interaction with co-authoring