diff --git a/lib/src/api/libraryBrowser/LibraryBrowserAPI.gf b/lib/src/api/libraryBrowser/LibraryBrowserAPI.gf
index e1e041213..53371fb96 100644
--- a/lib/src/api/libraryBrowser/LibraryBrowserAPI.gf
+++ b/lib/src/api/libraryBrowser/LibraryBrowserAPI.gf
@@ -45,9 +45,10 @@ oper mkTerm = overload {
     (t.par.p1 ++ t.f ++ t.x ++ t.par.p2 ++ fullTerm u ++ t.swap) ;
 
   hide : Str -> Str = \f -> [] ;
+  hideOpt : Str -> Str = \f -> [] | f ;
 
 lin AAnter = mkTerm "anteriorAnt" ;
-lin ASimul = mkTerm (hide "simultaneousAnt") ;
+lin ASimul = mkTerm (hideOpt "simultaneousAnt") ;
 lin AdAP ada_1 ap_2 = mkTerm "mkAP" ada_1 (flatIfTerm ap_2) ;
 lin AdAdv ada_1 adv_2 = mkTerm "mkAdv" ada_1 adv_2 ;
 lin AdNum adn_1 card_2 = mkTerm "mkCard" adn_1 card_2 ;
@@ -151,14 +152,14 @@ lin NumCard card_1 = mkTerm "mkNum" card_1 ;
 lin NumDigits digits_1 = mkTerm "mkCard" digits_1 ;
 lin NumNumeral numeral_1 = mkTerm "mkCard" numeral_1 ;
 lin NumPl = mkTerm "pluralNum" ;
-lin NumSg = mkTerm (hide "singularNum") ;
+lin NumSg = mkTerm (hideOpt "singularNum") ;
 lin OrdDigits digits_1 = mkTerm "mkOrd" digits_1 ;
 lin OrdNumeral numeral_1 = mkTerm "mkOrd" numeral_1 ;
 lin OrdSuperl a_1 = mkTerm "mkOrd" a_1 ;
 lin PConjConj conj_1 = mkTerm "mkPConj" conj_1 ;
 lin PNeg = mkTerm "negativePol" ;
 lin PPartNP np_1 v2_2 = mkTerm "mkNP" np_1 v2_2 ;
-lin PPos = mkTerm (hide "positivePol") ;
+lin PPos = mkTerm (hideOpt "positivePol") ;
 lin PassV2 v2_1 = mkTerm "passiveVP" v2_1 ;
 lin PhrUtt pconj_1 utt_2 voc_3 = mkFlat (mkTerm "mkPhr" pconj_1 utt_2 voc_3) ;
 lin PositA a_1 = mkFlat (mkTerm "mkAP" a_1) ;
@@ -202,13 +203,13 @@ lin SlashVP np_1 vpslash_2 = mkTerm "mkClSlash" np_1 vpslash_2 ;
 lin SlashVS np_1 vs_2 sslash_3 = mkTerm "mkClSlash" np_1 vs_2 sslash_3 ;
 lin SlashVV vv_1 vpslash_2 = mkTerm "mkVPSlash" vv_1 vpslash_2 ;
 lin SubjS subj_1 s_2 = mkTerm "mkAdv" subj_1 s_2 ;
-lin TEmpty = mkTerm (hide "emptyText") ;
+lin TEmpty = mkTerm (hideOpt "emptyText") ;
 lin TExclMark phr_1 text_2 = mkTerm "mkText" (flatIfTerm phr_1) (mkTerm "exclMarkPunct") text_2 ;
 lin TFullStop phr_1 text_2 = mkTerm "mkText" (flatIfTerm phr_1) text_2 ;
 lin TCond = mkTerm "conditionalTense" ;
 lin TFut = mkTerm "futureTense" ;
 lin TPast = mkTerm "pastTense" ;
-lin TPres = mkTerm (hide "presentTense") ;
+lin TPres = mkTerm (hideOpt "presentTense") ;
 lin TQuestMark phr_1 text_2 = mkTerm "mkText" (flatIfTerm phr_1) (mkTerm "questMarkPunct") text_2 ;
 lin TTAnt tense_1 ant_2 = mkTerm "mkTense" tense_1 ant_2 ;
 --lin Use2N3 n3_1 = mkTerm "mkN2" n3_1 ;