A tray holding muktzeh at Shabbat's onset itself becomes a "basis". Understand when the basis becomes forbidden and when a basis for both forbidden and permitted items remains permitted.
Per SA (OC 310:7; 309:4), an item on which muktzeh was deliberately placed, remaining so at twilight, becomes a basis and is forbidden to move all Shabbat - even if the muktzeh falls off.
A table with burning candlesticks and also challah and food is a basis for both, so it is not forbidden. That is why challah is placed on the table before Shabbat.
Proof that twilight is decisive: what was placed after Shabbat began does not make it a basis.
Check before Shabbat: what is on the table next to the candles?
One minute of planning before Shabbat saves questions all Shabbat.
Test yourself before marking the lesson complete.
When is basis status fixed?
