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Posted 29 Jun 2003


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XTipComboBox - Display tooltips for combobox

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4.47/5 (28 votes)
1 Jul 2003CPOL3 min read
XTipComboBox implements a combobox with tooltips for the data items (both in the list box and in the edit box)


XTipComboBox displays tooltips for a combobox, just like tooltips are displayed for a tree control whose items are too long to fit in tree control's client area. When a listbox item in combobox is too long to fit in the listbox, a tooltip will be displayed that allows viewing of complete text. Similarly, a tooltip is displayed when text in combo's edit box is too wide for edit box.

Here is how the tooltips look - note that the tooltip colors will match what is being tooltipped:




Implementation Notes

CXTipComboBox is derived from CComboBox, and implements one virtual function and four message handlers:
  • PreSubclassWindow() - this virtual function allows us to create tooltip window, add combobox as its tool, and perform other initialization. Note use of TTF_TRANSPARENT. This flag tells tooltip control to forward mouse messages (including mouse clicks) to the parent window. In the case of the listbox, this will prevent two CBN_SELENDOK messages from being sent to the parent dialog.

  • OnCtlColor() - This is not what you think. According to MSDN article HOWTO: Subclass CListBox and CEdit Inside of CComboBox (Q174667), this is actually recommended way of subclassing listbox of a combobox. We use this to subclass listbox only - for edit box, it is simpler to handle inside CXTipComboBox.

  • OnMouseMove() - This message handler catches mouse moves, and when mouse is inside combo client rect, tooltip will be activated.

  • OnTimer() - A timer is used only when a tooltip is being displayed. When code in OnTimer() detects that mouse is no longer inside client rect, tooltip is removed.

  • OnDestroy() - Unsubclasses the listbox.

Note that nearly identical code is implemented for first four functions in XTipComboBox.cpp and XTipListBox.cpp.

Tooltip Notes

As mentioned above, tooltip is created in PreSubclassWindow():
// create tooltip
m_hWndToolTip = ::CreateWindowEx(WS_EX_TOPMOST,
                          TTS_NOPREFIX | TTS_ALWAYSTIP,

// initialize toolinfo struct
memset(&m_ToolInfo, 0, sizeof(m_ToolInfo));
m_ToolInfo.cbSize = sizeof(m_ToolInfo);
m_ToolInfo.hwnd = m_hWnd;

// add combo box
::SendMessage(m_hWndToolTip, TTM_SETMAXTIPWIDTH, 0, SHRT_MAX);
::SendMessage(m_hWndToolTip, TTM_ADDTOOL, 0,
                                      (LPARAM) (LPTOOLINFO) &m_ToolInfo);
::SendMessage(m_hWndToolTip, TTM_SETTIPBKCOLOR,
                                      ::GetSysColor(COLOR_HIGHLIGHT), 0);
::SendMessage(m_hWndToolTip, TTM_SETTIPTEXTCOLOR,
                                  ::GetSysColor(COLOR_HIGHLIGHTTEXT), 0);

// reduce top & bottom margins
CRect rectMargins(0,-1,0,-1);
::SendMessage(m_hWndToolTip, TTM_SETMARGIN, 0, (LPARAM)&rectMargins);

// set font
CFont *pFont = GetFont();
::SendMessage(m_hWndToolTip, WM_SETFONT, (WPARAM)(HFONT)*pFont, FALSE);
In typical dialog box situations, you would need to use RelayEvent() along with LPSTR_TEXTCALLBACK to pass tooltip text to tooltip control. Since we are dealing with two separate controls (edit box and list box) wrapped in one combobox control, it is easier to intercept mouse moves and position the tooltip ourselves. Inside OnMouseMove(), we determine position of the mouse, get text underneath, and calculate whether text will fit inside client rect. If it won't fit, we display tooltip, using TTM_TRACKACTIVATE message. Here we also set text and background colors for tooltip, depending on what is being tooltipped. Finally, a timer is used to keep track of when mouse moves outside client rect, so that tooltip will be removed.

How To Use

To integrate CXTipComboBox into your app, you first need to add following files to your project:

  • XTipComboBox.cpp
  • XTipComboBox.h
  • XTipListBox.cpp
  • XTipListBox.h

Next, include header file XTipComboBox.h in appropriate project files (usually, dialog header files). Now you are ready to start using CXTipComboBox. If you already have a dialog box with combobox controls, just replace CComboBox with CXTipComboBox in the dialog header file. There is no extra initialization you need to do.

Demo App

The XTipComboBoxTest.exe demo shows how to use CXTipComboBox.

Revision History

Version 1.0 - 2003 June 30

  • Initial public release.


This software is released into the public domain. You are free to use it in any way you like. If you modify it or extend it, please to consider posting new code here for everyone to share. This software is provided "as is" with no expressed or implied warranty. I accept no liability for any damage or loss of business that this software may cause.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Hans Dietrich
Software Developer (Senior) Hans Dietrich Software
United States United States
I attended St. Michael's College of the University of Toronto, with the intention of becoming a priest. A friend in the University's Computer Science Department got me interested in programming, and I have been hooked ever since.

Recently, I have moved to Los Angeles where I am doing consulting and development work.

For consulting and custom software development, please see

Comments and Discussions

GeneralMy vote of 5 Pin
spott21-Aug-14 1:37
Memberspott21-Aug-14 1:37 
GeneralMy vote of 5 Pin
Manoj Kumar Choubey4-Apr-12 23:29
professionalManoj Kumar Choubey4-Apr-12 23:29 
GeneralMy vote of 5 Pin
Mona Bhujbal11-Jan-12 0:53
MemberMona Bhujbal11-Jan-12 0:53 
Generaltooltip flicker Pin
deshmukhshivkumar9-May-11 23:43
Memberdeshmukhshivkumar9-May-11 23:43 
GeneralTip window is hidden Pin
Andrew Phillips12-Jan-11 21:05
MemberAndrew Phillips12-Jan-11 21:05 
I have tried this with VS2008 and the tip window does not appear. Looking in Spy++ it is present but hidden.

I have tried all the re;evant suggestions below and none of them fixed the problem.

Also I can see calls to CreateWindow (to create the tip window) but no calls to DestroyWindow. Isn't this a nasty resource leak?
Andrew Phillips
andrew @

GeneralRe: Tip window is hidden Pin
Yunliang Wang7-Mar-15 21:25
professionalYunliang Wang7-Mar-15 21:25 
GeneralCXTipComboBox does not seem to work for me -- with VS2005 Pin
derejem13-Apr-10 1:23
Memberderejem13-Apr-10 1:23 
GeneralTop most window problem Pin
Elsie9-Nov-09 21:54
MemberElsie9-Nov-09 21:54 
GeneralTooltip flickers on vista machine Pin
gonsalvesroger20-Oct-09 23:38
Membergonsalvesroger20-Oct-09 23:38 
GeneralRe: Tooltip flickers on vista machine Pin
gonsalvesroger1-Nov-09 22:46
Membergonsalvesroger1-Nov-09 22:46 
GeneralCXTipComboBox derived from CComboBoxEx Pin
Md Saleem Navalur27-May-09 5:13
MemberMd Saleem Navalur27-May-09 5:13 
QuestionWhy it is not working in ATL Composte control ? Pin
Jagdish Vasani18-Oct-07 0:46
MemberJagdish Vasani18-Oct-07 0:46 
QuestionUsing this one without a manifest Pin
Markus Eßmayr13-Sep-07 0:56
MemberMarkus Eßmayr13-Sep-07 0:56 
AnswerRe: Using this one without a manifest Pin
Markus Eßmayr17-Sep-07 1:07
MemberMarkus Eßmayr17-Sep-07 1:07 
GeneralRe: Using this one without a manifest Pin
Jagdish Vasani18-Oct-07 3:50
MemberJagdish Vasani18-Oct-07 3:50 
QuestionCan this feature work in ASP. Pin
rachellim9-Aug-06 16:19
Memberrachellim9-Aug-06 16:19 
General.Net 2005 usage Pin
mikeh10-May-06 11:50
Membermikeh10-May-06 11:50 
GeneralRe: .Net 2005 usage Pin
HumanTargetJoe8-Aug-06 9:23
MemberHumanTargetJoe8-Aug-06 9:23 
GeneralVisual Basic Pin
Anonymous24-Aug-05 3:55
MemberAnonymous24-Aug-05 3:55 
GeneralIt does not work with "owner draw" boxes Pin
Member 79017625-Apr-05 2:36
MemberMember 79017625-Apr-05 2:36 
GeneralRe: It does not work with "owner draw" boxes Pin
Gilles066008-May-06 3:26
MemberGilles066008-May-06 3:26 
GeneralRe: It does not work with "owner draw" boxes Pin
microdus13-Feb-07 12:03
Membermicrodus13-Feb-07 12:03 
GeneralCompile error Pin
reiser4-Oct-04 21:51
Memberreiser4-Oct-04 21:51 
GeneralSlightly off-topic question: combo drop-down arrow Pin
David Pritchard22-Sep-04 6:56
MemberDavid Pritchard22-Sep-04 6:56 
GeneralBug and Fix Pin
Andrew115-Aug-04 3:06
MemberAndrew115-Aug-04 3:06 

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