diff --git a/lib/configure.py b/lib/configure.py
index 3a08c76232..921665be69 100644
--- a/lib/configure.py
+++ b/lib/configure.py
@@ -1150,8 +1150,8 @@ def processLayoutFile(file, bool_docbook):
             return x.strip()
     classname = file.split(os.sep)[-1].split('.')[0]
     # return ('LaTeX', '[a,b]', 'a', ',b,c', 'article') for \DeclareLaTeXClass[a,b,c]{article}
-    p = re.compile(r'\Declare(LaTeX|DocBook)Class\s*(\[([^,]*)(,.*)*\])*\s*{(.*)}')
-    q = re.compile(r'\DeclareCategory{(.*)}')
+    p = re.compile(r'^\s*#\s*\\Declare(LaTeX|DocBook)Class\s*(\[([^,]*)(,.*)*\])*\s*{(.*)}\s*$')
+    q = re.compile(r'^\s*#\s*\\DeclareCategory{(.*)}\s*$')
     classdeclaration = ""
     categorydeclaration = '""'
     for line in open(file).readlines():
@@ -1246,8 +1246,8 @@ def checkLatexConfig(check_config, bool_docbook):
     # Construct the list of classes to test for.
     # build the list of available layout files and convert it to commands
     # for chkconfig.ltx
-    declare = re.compile(r'\Declare(LaTeX|DocBook)Class\s*(\[([^,]*)(,.*)*\])*\s*{(.*)}')
-    category = re.compile(r'\DeclareCategory{(.*)}')
+    declare = re.compile(r'^\s*#\s*\\Declare(LaTeX|DocBook)Class\s*(\[([^,]*)(,.*)*\])*\s*{(.*)}\s*$')
+    category = re.compile(r'^\s*#\s*\\DeclareCategory{(.*)}\s*$')
     empty = re.compile(r'^\s*$')
     testclasses = list()
     for file in glob.glob( os.path.join('layouts', '*.layout') ) + \
diff --git a/src/LayoutFile.cpp b/src/LayoutFile.cpp
index 8ec7474a0a..26dfa849c7 100644
--- a/src/LayoutFile.cpp
+++ b/src/LayoutFile.cpp
@@ -287,9 +287,9 @@ LayoutFileIndex  LayoutFileList::addLocalLayout(
 	// which uses the following regex
 	//     \Declare(LaTeX|DocBook)Class\s*(\[([^,]*)(,.*)*\])*\s*{(.*)}
 	ifstream ifs(layout_file.toFilesystemEncoding().c_str());
-	static regex const reg("^#\\s*\\\\Declare(LaTeX|DocBook)Class\\s*"
+	static regex const reg("^\\s*#\\s*\\\\Declare(LaTeX|DocBook)Class\\s*"
 		"(?:\\[([^,]*)(?:,.*)*\\])*\\s*\\{(.*)\\}\\s*");
-	static regex const catreg("^#\\s*\\\\DeclareCategory\\{(.*)\\}");
+	static regex const catreg("^\\s*#\\s*\\\\DeclareCategory\\{(.*)\\}\\s*");
 	string line;
 	string class_name;
 	string class_prereq;
diff --git a/status.21x b/status.21x
index 1aaca2e5ea..e927ed64d5 100644
--- a/status.21x
+++ b/status.21x
@@ -80,6 +80,9 @@ What's new
 
 * INTERNALS
 
+- Fix parsing problems of class and category declaration line in layout files
+  that could break the textclass detection (bug 9746).
+
 
 
 * DOCUMENTATION AND LOCALIZATION