$('select').selectBox();

Standard Dropdown
Item 1 Item 2 Item 3 has a really long label that will not interfere with the control's width Item 4 Item 5 (disabled) Item 6 Item 7 Item 8 Item 9 Item 10 Item 11 Item 12 Item 13 Item 14 Item 15 Item 16 Item 17 Item 18 Item 19 Item 20 Item 2

Empty Dropdown
 

Multi-select Control
Item 1 Item 2 Item 3 Item 4 Item 5 (disabled)

• Item 1
• Item 2
• Item 3
• Item 4
• Item 5 (disabled)

Empty Multi-select

Multi-select with few options
Item 1 Item 2 Item 3

• Item 1
• Item 2
• Item 3

No multi-select, size = 4
Item 1 Item 2 Item 3 has <a> really long label but it won't affect the control's display at all Item 4 Item 5 (disabled)

• Item 1
• Item 2
• Item 3 has <a> really long label but it won't affect the control's display at all
• Item 4
• Item 5 (disabled)

Standard control with OPTGROUPS
Item 1 Item 2 Item 3 Item 4 Item 5 Item 6 Item 7 Item 8 Item 9 Item 10 Item 11 Item 12 Item 13 Item 14 Item 15 Item 16 Item 17 Item 18 Item 19 Item 20 Item 21 Item 22 Item 23 Item 24 Item 1

Multi-select control with OPTGROUPS
Item 1 Item 2 Item 3 Item 4 Item 5 Item 6 Item 7 Item 8 Item 9 Item 10 Item 11 Item 12 Item 13 Item 14 Item 15 Item 16 Item 17 Item 18 Item 19 Item 20 Item 21 Item 22 Item 23 Item 24

• Section 1
• Item 1
• Item 2
• Item 3
• Item 4
• Section 2
• Item 5
• Item 6
• Item 7
• Item 8
• Section 3
• Item 9
• Item 10
• Item 11
• Item 12
• Section 4
• Item 13
• Item 14
• Item 15
• Item 16
• Section 5
• Item 17
• Item 18
• Item 19
• Item 20
• Section 6
• Item 21
• Item 22
• Item 23
• Item 24

Dropdown positioned above control
Item 1 Item 2 Item 3 has a really long label that will not interfere with the control's width Item 4 Item 5 (disabled) Item 6 Item 7 Item 8 Item 9 Item 10 Item 11 Item 12 Item 13 Item 14 Item 15 Item 16 Item 17 Item 18 Item 19 Item 20 Item 2

Methods:

Values:

Transitions: