Cleanup: Add some comments removed in rB0d0036cb53f8

source/blender/editors/space_sequencer/sequencer_add.c

@@ -1038,7 +1038,7 @@ static int sequencer_add_effect_strip_exec(bContext *C, wmOperator *op)
     seq->blend_mode = SEQ_TYPE_ALPHAOVER;
   }
 
-  /* Set channel.*/
+  /* Set channel. If unset, use lowest free one above strips. */
   if (!RNA_struct_property_is_set(op->ptr, "channel")) {
     if (seq->seq1) {
       int chan = max_iii(seq->seq1 ? seq->seq1->machine : 0,

source/blender/editors/space_sequencer/sequencer_draw.c

@@ -353,6 +353,8 @@ static void draw_seq_waveform(View2D *v2d,
   }
 }
 
+/* Don't use SEQ_BEGIN/SEQ_END here, because it changes seq->depth,
+ * which is needed for tranform. */
 static void drawmeta_contents(Scene *scene, Sequence *seqm, float x1, float y1, float x2, float y2)
 {
   Sequence *seq;
@@ -1061,7 +1063,7 @@ static void draw_seq_fcurve(
   }
 }
 
-/* Draw visible strips. */
+/* Draw visible strips. Bounds check are already made. */
 static void draw_seq_strip(const bContext *C,
                            SpaceSeq *sseq,
                            Scene *scene,