ShellBrowser Delphi Components Documentation
Specifies the maximum number of characters the user can type into the edit portion of the combo box.
Use MaxLength to limit the number of characters that the user can enter into the edit portion of the combo box. A value of 0 indicates that there is no application-defined limit on the length.
Setting MaxLength will not truncate the existing text, it merely prevents the user from adding more text after reaching the limit of MaxLength characters.
Even when MaxLength is 0, there may be limitations imposed by the operating system on the number of characters that may be entered into an edit control.