Index: gc_core/js/lang_core/gc_engine.js
==================================================================
--- gc_core/js/lang_core/gc_engine.js
+++ gc_core/js/lang_core/gc_engine.js
@@ -1261,11 +1261,12 @@
 
 function select (dTokenPos, nPos, sWord, sPattern, lDefault=null) {
     if (!sWord) {
         return true;
     }
-    if (dTokenPos.has(nPos)) {
+    if (!dTokenPos.has(nPos)) {
+        console.log("Error. There should be a token at this position: ", nPos);
         return true;
     }
     let lMorph = _oSpellChecker.getMorph(sWord);
     if (lMorph.length === 0  ||  lMorph.length === 1) {
         return true;
@@ -1283,11 +1284,12 @@
 
 function exclude (dTokenPos, nPos, sWord, sPattern, lDefault=null) {
     if (!sWord) {
         return true;
     }
-    if (dTokenPos.has(nPos)) {
+    if (!dTokenPos.has(nPos)) {
+        console.log("Error. There should be a token at this position: ", nPos);
         return true;
     }
     let lMorph = _oSpellChecker.getMorph(sWord);
     if (lMorph.length === 0  ||  lMorph.length === 1) {
         return true;
@@ -1319,11 +1321,11 @@
             dToken["lMorph"] = lDefault;
         }
         return true;
     }
     let lSelect = lMorph.filter( sMorph => sMorph.search(sPattern) !== -1 );
-    if (lSelect) {
+    if (lSelect.length > 0) {
         if (lSelect.length != lMorph.length) {
             dToken["lMorph"] = lSelect;
         }
     } else if (lDefault) {
         dToken["lMorph"] = lDefault;
@@ -1339,11 +1341,11 @@
             dToken["lMorph"] = lDefault;
         }
         return true;
     }
     let lSelect = lMorph.filter( sMorph => sMorph.search(sPattern) === -1 );
-    if (lSelect) {
+    if (lSelect.length > 0) {
         if (lSelect.length != lMorph.length) {
             dToken["lMorph"] = lSelect;
         }
     } else if (lDefault) {
         dToken["lMorph"] = lDefault;