semantic-default-submodes

semantic-default-submodes is a variable defined in `semantic.el'.
Its value is

(global-semantic-idle-scheduler-mode global-semanticdb-minor-mode)

Documentation:
List of auxiliary Semantic minor modes enabled by `semantic-mode'.
The possible elements of this list include the following:

`global-semanticdb-minor-mode' - Maintain tag database.
`global-semantic-idle-scheduler-mode' - Reparse buffer when idle.
`global-semantic-idle-summary-mode' - Show summary of tag at point.
`global-semantic-idle-completions-mode' - Show completions when idle.
`global-semantic-decoration-mode' - Additional tag decorations.
`global-semantic-highlight-func-mode' - Highlight the current tag.
`global-semantic-stickyfunc-mode' - Show current fun in header line.
`global-semantic-mru-bookmark-mode' - Provide `switch-to-buffer'-like
keybinding for tag names.
`global-cedet-m3-minor-mode' - A mouse 3 context menu.
`global-semantic-idle-local-symbol-highlight-mode' - Highlight references
of the symbol under point.
The following modes are more targeted at people who want to see
some internal information of the semantic parser in action:
`global-semantic-highlight-edits-mode' - Visualize incremental parser by
highlighting not-yet parsed changes.
`global-semantic-show-unmatched-syntax-mode' - Highlight unmatched lexical
syntax tokens.
`global-semantic-show-parser-state-mode' - Display the parser cache state.

You can customize this variable.