>>>I just disabled (twice), and then enabled again. I also see only one name.
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>BTW, I tried to reproduce this situation, but couldn't. I tried double-clicking, and even enabling twice in different windows, but I couldn't reproduce this situation.
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>>Hannukkah was at the end of November this year...
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>If I remember correctly, the Jewish calender is of variable length, right? I read something about it having sometimes 12, sometimes 13 months (moons), to keep an average length of the year equal to the solar year.
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>Hilmar.

Yes. My husband wrote a little article about it (in Russian). Here is an excerpt in my translation:

Âàâèëîíñêèé êàëåíäàðü áûë ëóííî-ñîëíå÷íûì. Îí îñíîâûâàëñÿ íà ñîëíå÷íîì öèêëå (ãîä â 365,2425 äíåé) è ëóííîì ìåñÿöå (29,53059 äíåé). ×òîáû ïðèâåñòè ýòè ïåðèîäû â ñîîòâåòñòâèå äðóã ñ äðóãîì, ïðèõîäèòñÿ äîáàâëÿòü âðåìÿ îò âðåìåíè äîïîëíèòåëüíûé ìåñÿö. Çàèìñòâîâàâ êàëåíäàðü ó âàâèëîíÿí, åâðåè ïðèñïîñîáèëè åãî ê ñâîèì íóæäàì. Åâðåéñêèé êàëåíäàðü èñõîäèò èç ò.í. äåâÿòíàäöàòèëåòíåãî Ìåòîíîâà öèêëà (ïî èìåíè îòêðûâøåãî åãî ãðå÷åñêîãî àñòðîíîìà); 19 ñîëíå÷íûõ ëåò ñîîòâåòñòâóåò 235 ëóííûì ìåñÿöàì. Òðèíàäöàòûé ìåñÿö (Àäàð-âòîðîé) äîáàâëÿåòñÿ â òðåòèé, øåñòîé, âîñüìîé, îäèííàäöàòûé, ÷åòûðíàäöàòûé, ñåìíàäöàòûé è äåâÿòíàäöàòûé ãîäû öèêëà.
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Babilon calendar was moon - solar. It was based on solar cycle (365,2425 days in a year) and a moon montn (29,53059 days). In order to put these periods in correspondance with each other, we have to add an additional month from time to time. By borrowing calendar from Babilon, the jews adapted it for their needs. The Hebrew Calendar is based on so-called 19 years Meton cycle, 19 solar years correspond to 235 moon (loonar?) moths. The 13th month (Adar - second) is added on 3rd, 6th, 8th, 11th, 14th, 17th and 19th years of the cycle.