The collapsing of subprograms is faulty or at least not very intuitive. This should be improved. Let's assume the following function with suprograms:

Code
function mainFunction return number is
 var1 number;

 function subprog1 is
  [code]
 end subporg1;

 procedure subprog2 is
  [code]
 end subporg2;

begin

 [code]

end mainFunction;

Observed behavior:
If you collapse subprog1 in Developer subprog1 and subprog2 are actually collapsed. Code remains visible at "begin" of mainFunction.

Expected behavior:
Only the collapsed subprogram should actually be hidden and all code before an after should be fully visible.

Version 15.0.3.2059 (64 bit), Windows 10 Build 19045