The theme icon in latest update is missing(Settings>>Theme)

Before I can select the preferred theme but now the theme icon is on the obsolete

Welcome to the forum @Mo.Saleh

You need to write or paste something in order for your post to make sense.

And what is the problem? Why don’t you just click the icon?

There were a built in themes but now it is gone

if I clicked the new theme it navigate me to a developing window

Correct. Only custom themes are still available. This has already been discussed in the forum. You can use the search funtion to find those discussions.