diff --git a/seminar/admin.py b/seminar/admin.py
index 82df8fff..9ce11a93 100644
--- a/seminar/admin.py
+++ b/seminar/admin.py
@@ -347,7 +347,20 @@ class PohadkaAdminForm(forms.ModelForm):
         model = Pohadka
         exclude = []
     autor = UserModelChoiceField(User.objects.filter(is_staff=True))
-    uloha = forms.ModelChoiceField(Problem.objects.filter(typ=Problem.TYP_ULOHA))
+    uloha = forms.ModelChoiceField(
+        Problem.objects.filter(typ=Problem.TYP_ULOHA)
+    )
+
+    def __init__(self, *args, **kwargs):
+        super(PohadkaAdminForm, self).__init__(*args, **kwargs)
+        instance = getattr(self, 'instance', None)
+
+        # viz ProblemAdminForm.__init__
+        if instance and instance.pk:
+            if instance.uloha and instance.uloha.cislo_zadani:
+                if instance.uloha.cislo_zadani.faze != 'admin':
+                    self.fields['text'].widget.attrs['readonly'] = True
+
 
 class PohadkaAdmin(VersionAdmin):
     form = PohadkaAdminForm
@@ -361,12 +374,6 @@ class PohadkaAdmin(VersionAdmin):
         return obj.uloha.cislo_zadani.rocnik.rocnik
     get_rocnik.short_description = u'Ročník'
 
-    def get_readonly_fields(self, request, obj=None):
-        if not obj:
-            return []
-        if obj.uloha.cislo_zadani.faze != 'admin':
-            return ['text']
-
     list_display = [
         '__str__',
         'get_rocnik',
@@ -403,6 +410,38 @@ class ProblemAdminForm(forms.ModelForm):
         model = Problem
         exclude = []
 
+    def __init__(self, *args, **kwargs):
+        super(ProblemAdminForm, self).__init__(*args, **kwargs)
+        instance = getattr(self, 'instance', None)
+
+        # Nedovol měnit název a zadání resp. řešení, pokud je cislo_zadani
+        # resp. cislo_reseni mimo fázi admin.
+        #
+        # Nastavení readonly fields sice vypadá lépe (nevygeneruje input tag),
+        # ale při ukládání změny vypíše admin nespecifikovanou chybu, která je
+        # způsobena zřejmě tím, že se neodešle žádná hodnota pro povinné pole
+        # nazev. Navíc by se smazalo nepovinné pole zadání.
+        #
+        # Toto řešení je z http://stackoverflow.com/a/325038/4786205.
+        #
+        # TODO Django 1.9: použít field s atributem disabled?
+        if instance and instance.pk:
+            if instance.cislo_zadani and instance.cislo_zadani.faze != 'admin':
+                # CKEditor neumí readonly ...
+                self.fields['text_zadani'] = forms.CharField(
+                    widget=forms.Textarea,
+                    required=False
+                )
+                for f in ['nazev', 'text_zadani', 'body']:
+                    self.fields[f].widget.attrs['readonly'] = True
+            if instance.cislo_reseni and instance.cislo_reseni.faze != 'admin':
+                self.fields['text_reseni'] = forms.CharField(
+                    widget=forms.Textarea,
+                    required=False
+                )
+                self.fields['text_reseni'].widget.attrs['readonly'] = True
+
+
 class ProblemAdmin(VersionAdmin):
     form = ProblemAdminForm
     fieldsets = [
@@ -415,15 +454,7 @@ class ProblemAdmin(VersionAdmin):
     view_on_site = Problem.verejne_url
     ordering = ['-timestamp']
 
-    def get_readonly_fields(self, request, obj=None):
-        readonly_fields = ['timestamp', 'import_dakos_id']
-        if not obj:
-            return readonly_fields
-        if obj.cislo_zadani and obj.cislo_zadani.faze != 'admin':
-            readonly_fields += ['nazev', 'text_zadani', 'body']
-        if obj.cislo_reseni and obj.cislo_reseni.faze != 'admin':
-            readonly_fields += ['text_reseni']
-        return readonly_fields
+    readonly_fields = ['timestamp', 'import_dakos_id']
 
     def get_queryset(self, request):
         qs = super(ProblemAdmin, self).get_queryset(request)