Index: openacs-4/packages/acs-tcl/tcl/text-html-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-tcl/tcl/text-html-procs.tcl,v
diff -u -r1.109 -r1.109.2.1
--- openacs-4/packages/acs-tcl/tcl/text-html-procs.tcl	15 Dec 2018 17:46:28 -0000	1.109
+++ openacs-4/packages/acs-tcl/tcl/text-html-procs.tcl	1 Mar 2019 11:53:03 -0000	1.109.2.1
@@ -2042,8 +2042,22 @@
     set valid_froms { text/enhanced text/markdown text/plain text/fixed-width text/html text/xml }
     set valid_tos { text/plain text/html }
     # Validate procedure input
-    set from [ad_decode $from html text/html text text/plain plain text/plain pre text/plain $from]
-    set to   [ad_decode $to   html text/html text text/plain plain text/plain pre text/plain $to]
+    switch $from {
+        "html" {
+            set from text/html
+        }
+        "text" - "plain" - "pre" {
+            set from text/plain
+        }
+    }
+    switch $to {
+        "html" {
+            set to text/html
+        }
+        "text" - "plain" - "pre" {
+            set to text/plain
+        }
+    }
     return [expr {$from in $valid_froms && $to in $valid_tos}]
 }