diff --git a/src/cmd_context/cmd_context.cpp b/src/cmd_context/cmd_context.cpp
index 0d36e976b..e8f6ec6fa 100644
--- a/src/cmd_context/cmd_context.cpp
+++ b/src/cmd_context/cmd_context.cpp
@@ -1346,6 +1346,7 @@ void cmd_context::push() {
     s.m_macros_stack_lim       = m_macros_stack.size();
     s.m_aux_pdecls_lim         = m_aux_pdecls.size();
     s.m_assertions_lim         = m_assertions.size();
+    pm().push();
     unsigned timeout = m_params.m_timeout;
     m().limit().push(m_params.rlimit());
     cancel_eh<reslimit> eh(m().limit());
@@ -1474,6 +1475,7 @@ void cmd_context::pop(unsigned n) {
     restore_assertions(s.m_assertions_lim);
     restore_psort_inst(s.m_psort_inst_stack_lim);
     m_scopes.shrink(new_lvl);
+    pm().pop(n);
     while (n--) {
         m().limit().pop();
     }
diff --git a/src/cmd_context/pdecl.cpp b/src/cmd_context/pdecl.cpp
index a9688f64a..6aab2390b 100644
--- a/src/cmd_context/pdecl.cpp
+++ b/src/cmd_context/pdecl.cpp
@@ -716,9 +716,24 @@ void pdecl_manager::notify_datatype(sort *r, psort_decl* p, unsigned n, sort* co
             m.notify_new_dt(r, p);
         }
         m_notified.insert(r);
+        m_notified_trail.push_back(r);
     }
 }
 
+void pdecl_manager::push() {
+    m_notified_lim.push_back(m_notified_trail.size());
+}
+
+void pdecl_manager::pop(unsigned n) {
+    SASSERT(n > 0);
+    unsigned new_sz = m_notified_lim[m_notified_lim.size() - n];
+    for (unsigned i = m_notified_trail.size(); i-- > new_sz; ) {
+        m_notified.erase(m_notified_trail[i]);
+    }
+    m_notified_trail.shrink(new_sz);
+    m_notified_lim.shrink(m_notified_lim.size() - n);
+}
+
 bool pdatatypes_decl::instantiate(pdecl_manager & m, sort * const * s) {
     UNREACHABLE();
     return false;
diff --git a/src/cmd_context/pdecl.h b/src/cmd_context/pdecl.h
index 8f8c94dcc..d65b52ae8 100644
--- a/src/cmd_context/pdecl.h
+++ b/src/cmd_context/pdecl.h
@@ -288,6 +288,8 @@ class pdecl_manager {
 
     obj_map<sort, sort_info *>   m_sort2info; // for pretty printing sorts
     obj_hashtable<sort>          m_notified;
+    ptr_vector<sort>             m_notified_trail;
+    unsigned_vector              m_notified_lim;
 
     void init_list();
     void del_decl_core(pdecl * p);
@@ -318,6 +320,8 @@ public:
     sort * instantiate_datatype(psort_decl* p, symbol const& name, unsigned n, sort * const* s);
     sort * instantiate(psort * s, unsigned num, sort * const * args);
     void notify_datatype(sort *r, psort_decl* p, unsigned n, sort* const* s);
+    void push();
+    void pop(unsigned n);
 
     void lazy_dec_ref(pdecl * p) { p->dec_ref(); if (p->get_ref_count() == 0) m_to_delete.push_back(p); }
     template<typename T>
diff --git a/src/smt/seq_regex.cpp b/src/smt/seq_regex.cpp
index 6f3da301b..c10a4ded2 100644
--- a/src/smt/seq_regex.cpp
+++ b/src/smt/seq_regex.cpp
@@ -293,7 +293,7 @@ namespace smt {
                 conds.push_back(lcond);
                 d = el;
                 break;
-            case l_undef: 
+            case l_undef:
 #if 1
                 ctx.mark_as_relevant(lcond);
                 trigger = lcond;
@@ -315,6 +315,7 @@ namespace smt {
                 }
                 else {
                     ctx.mark_as_relevant(lcond);
+                    trigger = lcond;
                     return false;
                 }
                 break;
diff --git a/src/smt/theory_seq.cpp b/src/smt/theory_seq.cpp
index 01f222aa8..1ec005ac8 100644
--- a/src/smt/theory_seq.cpp
+++ b/src/smt/theory_seq.cpp
@@ -2331,7 +2331,7 @@ theory_var theory_seq::mk_var(enode* n) {
 }
 
 bool theory_seq::can_propagate() {
-    return m_axioms_head < m_axioms.size() || !m_replay.empty() || m_new_solution || m_unicode.can_propagate();
+    return m_axioms_head < m_axioms.size() || !m_replay.empty() || m_new_solution || m_unicode.can_propagate() || m_regex.can_propagate();
 }
 
 bool theory_seq::canonize(expr* e, dependency*& eqs, expr_ref& result) {