diff --git a/0002-vx b/0002-vx
index 15f794b..065d2c5 100644
--- a/0002-vx
+++ b/0002-vx
@@ -1,3 +1,4 @@
-vx = function(x)
-	return scale(x-Viewport.x)
-end
\ No newline at end of file
+vx = function(sx)
+	-- turn surface coordinates into viewport coordinates
+	return scale(sx-Viewport.x)
+end
diff --git a/0004-vy b/0004-vy
index 5fb9f8c..8e4e23e 100644
--- a/0004-vy
+++ b/0004-vy
@@ -1,3 +1,4 @@
-vy = function(y)
-	return scale(y-Viewport.y)
-end
\ No newline at end of file
+vy = function(sy)
+	-- turn surface coordinates into viewport coordinates
+	return scale(sy-Viewport.y)
+end
diff --git a/0006-on.mouse_press b/0006-on.mouse_press
index 52a00c6..faa26bf 100644
--- a/0006-on.mouse_press
+++ b/0006-on.mouse_press
@@ -5,9 +5,11 @@ on.mouse_press = function(x,y, mouse_button)
 	end
 	local node = to_text(x,y)
 	if node then
+		-- position cursor in node
 		Cursor_node = node
 		edit.mouse_press(node.editor, x,y, mouse_button)
-	else
-		Pan = {x=Viewport.x+x/Viewport.zoom,y=Viewport.y+y/Viewport.zoom}
+		return
 	end
+	-- pan surface
+	Pan = {x=Viewport.x+x/Viewport.zoom,y=Viewport.y+y/Viewport.zoom}
 end
diff --git a/0011-box_height b/0011-box_height
index 8ecf97b..ca50708 100644
--- a/0011-box_height
+++ b/0011-box_height
@@ -1,16 +1,16 @@
 box_height = function(node)
-	-- return the height of a node. The result is scaled.
-  local y = 0
-  for i=1,#node.editor.lines do
-    local line = node.editor.lines[i]
-    if node.editor.line_cache[i] == nil then
-      node.editor.line_cache[i] = {}
-    end
-    node.editor.line_cache[i].fragments = nil
-    node.editor.line_cache[i].screen_line_starting_pos = nil
-    Text.populate_screen_line_starting_pos(node.editor, i)
-    y = y + node.editor.line_height*#node.editor.line_cache[i].screen_line_starting_pos
-    Text.clear_screen_line_cache(node.editor, i)
-  end
-  return y
+	-- return the height of a text editor node (explicit width). The result is unscaled.
+	local y = 0
+	for i=1,#node.editor.lines do
+		local line = node.editor.lines[i]
+		if node.editor.line_cache[i] == nil then
+			node.editor.line_cache[i] = {}
+		end
+		node.editor.line_cache[i].fragments = nil
+		node.editor.line_cache[i].screen_line_starting_pos = nil
+		Text.populate_screen_line_starting_pos(node.editor, i)
+		y = y + 20*1.3*#node.editor.line_cache[i].screen_line_starting_pos
+		Text.clear_screen_line_cache(node.editor, i)
+	end
+	return y
 end
diff --git a/0017-on.mouse_release b/0017-on.mouse_release
index 0a14bf4..5c987a0 100644
--- a/0017-on.mouse_release
+++ b/0017-on.mouse_release
@@ -1,8 +1,9 @@
 on.mouse_release = function(x,y, mouse_button)
 	if Pan then
 		Pan = nil
+		A()
 	elseif Cursor_node then
 		Cursor_node.show_cursor = true
 		edit.mouse_release(Cursor_node.editor, x,y, mouse_button)
 	end
-end
\ No newline at end of file
+end