diff --git a/data/core/doc/init.lua b/data/core/doc/init.lua
index 74116fd5..572b2d78 100644
--- a/data/core/doc/init.lua
+++ b/data/core/doc/init.lua
@@ -44,7 +44,12 @@ end
 
 function Doc:reset_syntax()
   local header = self:get_text(1, 1, self:position_offset(1, 1, 128))
-  local syn = syntax.get(self.filename or "", header)
+  local path = self.abs_filename
+  if not path and self.filename then
+    path = core.project_dir .. PATHSEP .. self.filename
+  end
+  if path then path = common.normalize_path(path) end
+  local syn = syntax.get(path or "", header)
   if self.syntax ~= syn then
     self.syntax = syn
     self.highlighter:soft_reset()
diff --git a/data/core/syntax.lua b/data/core/syntax.lua
index 6fe8984a..977983c1 100644
--- a/data/core/syntax.lua
+++ b/data/core/syntax.lua
@@ -44,7 +44,7 @@ local function find(string, field)
 end
 
 function syntax.get(filename, header)
-  return find(common.basename(filename), "files")
+  return find(filename, "files")
       or (header and find(header, "headers"))
       or plain_text_syntax
 end