So you clicked on the menu, huh?

Menu Dropdown




I put a breakpoint at libo/vcl/source/window/winproc.cxx:2405, at the case SAL_EVENTMOUSEDOWN, to see

what happens when I click a mouse. 




I clicked on File Menu, it hit the breakpoint. Then off it goes to calls ImplHandleSalMouseButtonDown () 

with the following details stored in pEvent and pWindow.




pEvent

    mnTime = 78764380 //Time

    mnX = 18 //x co-ordinate

    mnY = 9  //y co-ordinate

    mnButton = 1  //left button, 4 for right click, 2 for clicking with the scroller

    mnCode = 0  //to find whether click is part of some select etc.




pWindow - the window object.

    

The ImplHandleSalMouseButtonDown () function is in ./libo/vcl/source/window/winproc.cxx:2068, it checks

whether shift, ctrl or alt keys were pressed in 2076, and then calls ImplGetMouseButtonMode () with pEvent

(function is at ./libo/vcl/source/window/winproc.cxx:2030) to get further details of whether it is a simple

click event or whether it is part of select, multi (ctrl+click?) or range select, using pEvent's mnCode 

variable. 




The ImplGetMouseButtonMode () function returns nMode as 3. The first two if statements were true, ie.

MOUSE_SIMPLECLICK and MOUSE_SELECT. Once, this returns, ImplHandleSalMouseButtonDown () calls the function

ImplHandleMouseEvent (), with 




    - the window object - pWindow

    - nSVEvent = 1 (EVENT_MOUSEBUTTONDOWN)

    - bMouseLeave = False

    - x,y co-ordinates

    - time of the event nMsgTime

    - nCode = 1, to indicate status of shift,ctrl keys

    - and mode of click , nMode = 3




The function then does the following,

    - gets the details of the frame 

    - checks the previous location of the mouse. 

    - updates the frame data with the latest details 

    - checks whether the mouse has left or entered (?). 

    - finds the window

    - after finding the window 

        - it checks whether the window was disabled

    - it comes to line 666 (after several if conditions turned out to be false), for the mouse click event

        - here it checks for double click.

        - it then updates the details in the child window object

    - It creates the MouseEvent object at line 709

    - It notifies the child window of the event. Off to the next function.

    - In the next call, first the constructor of ImplDelData is called (maybe due to some 

        inheritance) ImplDelData::ImplDelData () at /home/jesso/Downloads/libreoffice/libo/vcl/inc/

        svdata.hxx:424, this is there to protect against the window from getting destroyed.

    - The NotifyEvent object is created.

    - It then checks whether it should bring the window into focus, if it previously didn't have focus,

        close context menus etc.

    - ImplCallPreNotify function

        - calls long Application::CallEventHooks () at ./libo/vcl/source/app/svapp.cxx:1657

        - that function returns 0

        - so it gets the PreNotify () method on the window object in the event object.

    - Finally it calls the MouseButtonDown() method on the pChild pointer, which happens to be 

          MenuBarWindow::MouseButtonDown () at ./libo/vcl/source/window/menu.cxx:5366




The MenuBarWindow::MouseButtonDown () then does the following,

    - It first finds the entry on which the action happened.

    - It then calls ChangeHighlightItem (which needs to be refactored, btw)

    - This decides whether to update the focus etc

    - It then finally creates the pop up in line 5477