CC3 drawings have sheets which contain related entities. Different effects can be assigned to each sheet.
Click Sheets and Effects 
to control these settings
Click the Sheets indicator, even in mid-command to control just sheets.
CC3's drawing tools optionally add their entities onto specific sheets.
CC3's symbols can place themselves on appropriate sheets.
Both the drawing tools and the symbols support wild cards in sheet names. For example, if you place a Mountain symbol, it will by default go on the SYMBOLS layer. If the current layer starts with the word SYMBOLS, it will go there instead. This lets you add custom sheets.
To override the default sheets for drawing tools, click the Drawing Tools 
button, then the Insert on Sheet option in the drawing tool dialog box.
To override the default sheets for symbols, click Symbol Catalog Options, then unckeck the Symbols choose their own sheets check box.