This is a list of CSS classes used to mark Gantt chart elements. 

All class names will be prefixed with theme property value. For theme="gantt_default" this means _message will result in gantt_default_message class.

Message Box

_message

Message bar.

_message_close

Close icon of the message bar.

Task Boxes

_event

Main task box

_event_inner

Inner task box.

_event_float

The floating div overlay displayed when the task box start is not in the viewport.

_event_float_inner

Inside _event_float.

_event_delete

Built-in delete icon.

_selected

A selected task box (in addition to _event).

_event_bar

 Complete bar background, full width. Inside _event.

_event_bar_inner

The percentage part of the complete bar. Inside _event_bar.

_event_continueleft

Task boxes that start outside of the visible area.

_event_continueright

Task boxes that end outside of the visible area.

_task_group

Task group box. In addition to _event.

_task_milestone

Milestone box. In addition to _event.

_event_left

A div displaying custom text next to the task (on the left).

_event_right

A div displaying custom text next to the task (on the right).

Links

_link_horizontal

Horizontal line, part of a link.

_link_vertical

Vertical line, part of a link.

_link_arrow_right

End of a link, an arrow pointing right.

_link_arrow_left

End of a link, an arrow pointing left.

_link_arrow_down

End of a link, an arrow pointing down.

_link_hover

Added to all links elements when the link is focused (on hover).

Drag and Drop Shadow

_shadow

Moving/resizing shadow marker.

_shadow_inner

Inside _shadow.

_event_move_left

Position indicator div next to the shadow (on the left).

_event_move_right

Position indicator div next to the shadow (on the right).

_shadow_overlap

Added to _shadow when the shadow overlaps an existing event.

Rows

_resourcedivider

1px horizontal line between rows in the resource header.

_rowheader

Applied to every cell in the row header, including additional columns.

_rowheader_selected

Applied to every header cell in a selected row, in addition to _rowheader.

_rowheadercol

Applied to additional columns, in addition to _rowheader.

_rowheadercolX 

Additional columns, in addition to _rowheadercol and _rowheader.

Examples: _rowheadercol1, _rowheadercol2

_rowheader_inner

Inside _rowheader.

_tree_image_expand

Expand icon box. Inside _rowheader and _rowheader_inner.

_tree_image_collapse

Collapse icon box. Inside _rowheader and _rowheader_inner.

_tree_image_no_children

No children icon box. Inside _rowheader and _rowheader_inner.

_rowmove_handle

The drag handle used for row moving.

_rowmove_source

An overlay div created over the source row header during row moving.

_rowmove_position_before

Target position indicator during row moving ("before").

_rowmove_position_after

Target position indicator during row moving ("after").

_rowmove_position_child

Target position indicator during row moving ("child").

_rowmove_position_forbidden

Target position indicator during row moving ("forbidden").

_header_icon

The hide/show icon in the upper-left corner of the viewport that will let you hide and show the row header.

_header_icon_hide

Used for the icon when the row header is visible (in addition to _header_icon).

_header_icon_show

Used for the icon when the row header is hidden (in addition to _header_icon).

Columns

_columnheader

A div that includes the column header cells.

_columnheader_inner

Inside _columnheader.

_columnheader_cell

Column header cell.

_columnheader_cell_inner

Inside _columnheader_cell.

_columnheader_splitter

Splitter div between two columns.

Main

_main

The topmost div.

_splitter

The vertical splitter line between resources and the time part.

_divider_horizontal

Horizontal 1px line between upper-left corner and resources.

_block

An overlay div used to block the Gantt control during CallBacks.

Upper-Left Corner Cell

_corner

Upper-left corner box.

_corner_inner

Inside _corner.

Time Grid

_scrollable

Main scrollable area with time cells.

_matrix

 Grid with time cells, inside _scrollable.

_loading

Loading label.

_matrix_horizontal_line

 1px horizontal line between time cells.

_matrix_vertical_line

1px vertical line between time cells.

_matrix_vertical_break

1px vertical line placed over _matrix_vertical_line if there is a time break at this point - a hidden column for ShowNonBusiness=false.

Grid Cells

_cell

Time cell. Only in full rendering mode (see _cellcolumn below).

_cell_business

Cells marked as business. In addition to _cell.

_cell_selected

Cells in a selected row. In addition to _cell.

Time Header

_timeheadercol

Time header cells.

_timeheadercol_inner

Inside _timeheadercol.