Comment changes.

Components/ScintEdit.pas

@@ -1832,6 +1832,8 @@ procedure TScintEdit.StyleNeeded(const EndPos: Integer);
       var OldState := FLines.GetState(I);
       if FStyler.FLineState <> OldState then
         Call(SCI_SETLINESTATE, I, FStyler.FLineState);
+      { To display/debug fold levels use: Call(SCI_SETFOLDFLAGS, SC_FOLDFLAG_LEVELNUMBERS, 0);
+        And then also update UpdateLineNumbersWidth to make the margin wider. }
       var OldLevel := Call(SCI_GETFOLDLEVEL, I, 0);
       if FoldLevel <> OldLevel then
         Call(SCI_SETFOLDLEVEL, I, FoldLevel);

Components/ScintStylerInnoSetup.pas

@@ -21,7 +21,8 @@ interface
 
 type
   TInnoSetupStylerSection = (
-    scNone,            { Not inside a section (start of file, or last section was closed) }
+    scNone,            { Not inside a section (start of file, or previous section was closed with )
+                         Section tags themselves are not associated with any section! }
     scUnknown,         { Inside an unrecognized section }
     scThirdParty,      { Inside a '_' section (reserved for third-party tools) }
     scCode,
@@ -939,24 +940,26 @@ function TInnoSetupStyler.GetFlagsWordList(Section: TInnoSetupStylerSection): An
 procedure TInnoSetupStyler.GetFoldLevel(const LineState: TScintLineState;
   var Level: Integer; var Header: Boolean);
 begin
+  { Set folding per section. To keep our code as simple as possible we simply
+    give all lines outside of a section (=lines at the start of the document and
+    section tags and section end tags and lines after section end tags) a header
+    flag. This avoids having to look at the previous line. Doesn't mean
+    Scintilla will display folding markers on all these header lines: it only
+    does that when there is something to fold, so when the header line is
+    followed a by non-header line which is only the case for a section tag line
+    followed by a section line.
+
+    Did notice an issue (Scintilla automatic folding bug?): Add a section with
+    some lines. Collapse it. Break the section header for example by removing ']'.
+    Scintialla now auto expands the section and removes the fold mark.
+    Retype the ']'. Scintilla now displays the old fold mark to expand the
+    section but it's already expanded.  }
+
   var Section := TInnoSetupStyler.GetSectionFromLineState(LineState);
   if Section <> scNone then begin
     Level := 1;
     Header := False;
   end else begin
-  { Everything outside a section should have the header flag, even if it's just
-    a blank line or a comment. Doing this doesn't cause many fold markers: if
-    two lines have the same level and header flag the first line doesn't get a
-    fold mark since there's nothing to expand. Not doing this however is a
-    problem: for example, if the first line is empty and and the second line
-    starts a section then those two lines would logically considered to be in
-    the same 'fold' and edits on the first line would affect the section if
-    collapsed.
-    Did notice an issue (Scintilla bug?): Add a section with some lines.
-    Collapse it. Break the section header for example by removing ']'.
-    Scintialla now auto expands the section and removes the fold mark.
-    Retype the ']'. Scintilla now displays the old fold mark to expand the
-    section but it's already expanded.  }
     Level := 0;
     Header := True;
   end;