MUI2 finish page two lines for run

I'm moving to MUI2 and have a problem with the finish page.
I used the run checkbox to start my function and the text for the checkbox was to long for one line so I used that code to make it two lines high.
But it does not work any more since MUI2 is based on nsDialog. So how could I do the same for MUI2?

Function fin_pre

    ;two lines for the install checkbox

    WriteINIStr "$PLUGINSDIR\iospecial.ini" "Field 4" "Bottom" "120"

FunctionEnd

To modify MUI2's default pages, check the files in your NSIS\Contrib\Modern UI 2\Pages directory and look for variables such as mui.FinishPage.Run . They contain the HWND of the dialog (visual object). Use that HWND to change the dialog's properties (in the page SHOW function, if I recall correctly).

thanks MSG for the right direction,

so now I have the handle of the checkbox and can check/uncheck it using SendMessage.

I also found the right function to resize it, but first I want to get the position of the checkbox inside the window. System plugin is a powerfull tool, but I cannot get the result I wish, so I hope someone can help.

here is the code wich should get the coordinates of the checkbox (RECT), but all values I get back are 0.

    System::Alloc 16

    Pop $1

    System::Call "User32::GetClientRect (i $mui.FinishPage.Run,i r1)"

    ;System::Call "User32::GetWindowRect (i $HWNDPARENT, i r1)"

    System::Call "*$1(i .r2, i .r3, i .r4, i .r5)"

    System::Free $1



    MessageBox MB_OK|MB_ICONEXCLAMATION "left: $2 $\r$\n top: $3 $\r$\n right: $4 $\r$\n bottom: $5"

All right, the definition of the called function was wrong

this works:

System::Call "User32::GetClientRect(i, i) i ($mui.FinishPage.Run, r1) .r9"

Here is the complete code for resizing the checkbox, can be also used to resize any control.

    ; allocate memory for RECT structure

    System::Alloc 16

    Pop $1

    ; Get the current height of the checkbox, save it in $2 and make it double size

    ; save the width too

    System::Call "User32::GetClientRect(i, i) i ($mui.FinishPage.Run, r1) .r9"

    System::Call "*$1(i , i , i .r3, i .r2)"

    IntOp $2 $2 * 2

    

    ; get the position of the window and the position of the checkbox to

    ; calculate the relative position (top,left corner) of the checkbox inside the window

    System::Call "User32::GetWindowRect(i, i) i ($HWNDPARENT, r1) .r9"

    System::Call "*$1(i .r6, i .r7, i, i)"

    

    System::Call "User32::GetWindowRect(i, i) i ($mui.FinishPage.Run, r1) .r9"

    System::Call "*$1(i .r4, i.r5, i, i)"

    System::Free $1

    

    ; save x in $4 and y in $5

    IntOp $4 $4 - $6

    IntOp $5 $5 - $7



    ; resize the control using MoveWindow call and force redraw

    System::Call "User32::MoveWindow(i, i, i, i, i, i) b ($mui.FinishPage.Run, $4, $5, $3, $2, 1)"