Fixed line selection calculation.

gtk3maxgui.mod/gtkcommon.bmx

@@ -503,6 +503,7 @@ Extern
 	' GtkTextIter
 	Function gtk_text_iter_get_line:Int(handle:Byte Ptr)
 	Function gtk_text_iter_get_offset:Int(handle:Byte Ptr)
+	Function gtk_text_iter_backward_char:Int(handle:Byte Ptr)
 	
 	' GtkTextTagTable
 	Function gtk_text_tag_table_lookup:Byte Ptr(handle:Byte Ptr, txt$z)

gtk3maxgui.mod/gtkgadget.bmx

@@ -5094,8 +5094,10 @@ Type TGTKDefaultTextArea Extends TGTKTextArea
 		If hasSelection Then
 
 			If units = TEXTAREA_LINES Then
+			
+				gtk_text_iter_backward_char(_end)
 
-				length = gtk_text_iter_get_line(_end) - gtk_text_iter_get_line(_start)
+				length = (gtk_text_iter_get_line(_end) - gtk_text_iter_get_line(_start)) + 1
 
 			Else ' must be TEXTAREA_CHARS