Issue #12590: IDLE editor window now always displays the first line

when opening a long file.  With Tk 8.5, the first line was hidden.

Lib/idlelib/IOBinding.py

@@ -266,7 +266,7 @@ class IOBinding:
         self.reset_undo()
         self.set_filename(filename)
         self.text.mark_set("insert", "1.0")
-        self.text.see("insert")
+        self.text.yview("insert")
         self.updaterecentfileslist(filename)
         return True
 

Misc/NEWS

@@ -277,6 +277,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #12590: IDLE editor window now always displays the first line
+  when opening a long file.  With Tk 8.5, the first line was hidden.
+
 - Issue #12161: Cause StringIO.getvalue() to raise a ValueError when used on a
   closed StringIO instance.