Fix multiple entries allowed in crossref

Fixed issue JabRef#5284 where multiple entries were allowed in crossref field, whereas only one should be allowed. JabRef#5284

AUTHORS

@@ -104,6 +104,7 @@ Jörg Lenhard
 Jörg Wegner
 Jörg Zieren
 Jørgen Kvalsvik
+Julien Benard
 Jürgen Lange
 Kai Mindermann
 Karsten Hiekmann
@@ -117,6 +118,7 @@ Leonardo Haddad
 Ling Wang
 Linus Dietz
 Lorenzo Genta
+Lucas Beretti
 Luciana de Melo e Abud
 Mairieli Wessel
 Manuel Siebeneicher
@@ -200,6 +202,7 @@ Toralf Senger
 Ulrich Stärk
 Ulrik Stervbo
 Uwe Kuehn
+Venceslas Roullier
 Vincent W. Yang
 Waida Fan
 Waluyo Adi Siswanto

CHANGELOG.md

@@ -26,7 +26,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - The "All entries group" is no longer shown when no library is open.
 - We fixed an exception which occurred when closing JabRef. [#5348](https://github.com/JabRef/jabref/issues/5348)
 - We fixed a few problems that prevented JabFox to communicate with JabRef. [#4737](https://github.com/JabRef/jabref/issues/4737) [#4303](https://github.com/JabRef/jabref/issues/4303)
-- We fixed an error where the groups containing an entry loose their highlight color when scrolling. [#5022](https://github.com/JabRef/jabref/issues/5022) 
+- We fixed an error where the groups containing an entry loose their highlight color when scrolling. [#5022](https://github.com/JabRef/jabref/issues/5022)
 - We fixed an error where an exception was thrown when merging entries. [#5169](https://github.com/JabRef/jabref/issues/5169)
 - After assigning an entry to a group, the item count is now properly colored to reflect the new membership of the entry. [#3112](https://github.com/JabRef/jabref/issues/3112)
 - The group panel is now properly updated when switching between libraries (or when closing/opening one). [#3142](https://github.com/JabRef/jabref/issues/3142)
@@ -37,7 +37,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We fixed an issue where multiple entries were highlighted in the web search result after scrolling. [#5035](https://github.com/JabRef/jabref/issues/5035)
 - We fixed an issue where the hover indication in the web search pane was not working. [#5277](https://github.com/JabRef/jabref/issues/5277)
 - We fixed an error mentioning "javafx.controls/com.sun.javafx.scene.control" that was thrown when interacting with the toolbar.
-- We fixed an error where a cleared search was restored after switching libraries. [#4846](https://github.com/JabRef/jabref/issues/4846) 
+- We fixed an error where a cleared search was restored after switching libraries. [#4846](https://github.com/JabRef/jabref/issues/4846)
 - We fixed an exception which occurred when trying to open a non-existing file from the "Recent files"-menu [#5334](https://github.com/JabRef/jabref/issues/5334)
 - We fixed an issues where the search highlight in the entry preview did not worked. [#5069](https://github.com/JabRef/jabref/issues/5069)
 - The context menu for fields in the entry editor is back. [#5254](https://github.com/JabRef/jabref/issues/5254)
@@ -46,11 +46,11 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We re-introduced the feature to switch between different preview styles. [#5221](https://github.com/JabRef/jabref/issues/5221)
 - We fixed various issues (including [#5263](https://github.com/JabRef/jabref/issues/5263)) related to copying entries to the clipboard
 - We fixed some display errors in the preferences dialog and replaced some of the controls [#5033](https://github.com/JabRef/jabref/pull/5033) [#5047](https://github.com/JabRef/jabref/pull/5047) [#5062](https://github.com/JabRef/jabref/pull/5062) [#5141](https://github.com/JabRef/jabref/pull/5141) [#5185](https://github.com/JabRef/jabref/pull/5185) [#5265](https://github.com/JabRef/jabref/pull/5265) [#5315](https://github.com/JabRef/jabref/pull/5315) [#5360](https://github.com/JabRef/jabref/pull/5360)
-- We fixed an exception which occurred when trying to import entries without an open library. [#5447](https://github.com/JabRef/jabref/issues/5447) 
+- We fixed an exception which occurred when trying to import entries without an open library. [#5447](https://github.com/JabRef/jabref/issues/5447)
 - After successful import of one or multiple bib entries the main table scrolls to the first imported entry [#5383](https://github.com/JabRef/jabref/issues/5383)
 - We fixed an exception which occurred when an invalid jstyle was loaded. [#5452](https://github.com/JabRef/jabref/issues/5452)
 - We fixed an error where the preview theme did not adapt to the "Dark" mode [#5463](https://github.com/JabRef/jabref/issues/5463)
-
+- We fixed an issue where multiple entries were allowed in the "crossref" field [#5284](https://github.com/JabRef/jabref/issues/5284)
 ### Removed
 
 
@@ -151,7 +151,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We optimized the code responsible for connecting to an external database, which should lead to huge improvements in performance.
 - For automatically created groups, added ability to filter groups by entry type. [#4539](https://github.com/JabRef/jabref/issues/4539)
 - We added the ability to add field names from the Preferences Dialog [#4546](https://github.com/JabRef/jabref/issues/4546)
-- We added the ability to change the column widths directly in the main 
+- We added the ability to change the column widths directly in the main
 . [#4546](https://github.com/JabRef/jabref/issues/4546)
 - We added a description of how recommendations were chosen and better error handling to Related Articles tab
 - We added the ability to execute default action in dialog by using with <kbd>Ctrl</kbd> + <kbd>Enter</kbd> combination [#4496](https://github.com/JabRef/jabref/issues/4496)