Win32 API dialogbox stalls/freezes on moving it - winapi

Question

I have a modless Win32 API dialogbox as status box with a LISTBOX in it where I print some information of the communication between an IDE and the MSSCCI provider.
Everything works fine (the status messages are printed line by line and scrolled) unless I, as a IDE user, touch the status- dialogbox and try to move it around.
Then the status updating freezes (when clicking on the status dialogbox several times the "not responding" appear in the title bar) and with it the parent application (an IDE).
The program seems still to be running in the background (I also log to a file where the progress is "visible").
The dialogobox is not destroyed but hidden by the application when the task (getting several file from the repo) has finished. Later when a new task is started the dialogbox is shown again, the status message of the newly started task get printed and scrolled again as if nothing had happend.
I tried to catch the WM_MOVE and WM_MOVING in the dialogboxes callback function, set the statusbox the active window (see code). Nothing helped so far.
What do I have to do that the dialogbox does not freeze when the user moves it?
Any hints?
(By the way, when debugging, I can not move the dialogbox and the listbox in the dialogbox gets updated all the time and the parent get redrawn too)
Here some code (file processing loop):
pool = svnApiSvnIface.fp_svn_pool_create_ex(masterPool, NULL);
for(i=0; i<nFiles; i++)
{
WaspLoggerLogPrintf(0, "%s - Processing: '%s' \n",
__FUNCTION__,
StripFilename(lpFileNames[i]));
UpdateWindow(hwndParent);
SetActiveWindow (hwndStatusBox);
PrintMesgStatusBox("CheckFileStatus: for %s", StripFilename(lpFileNames[i]));
revison.kind = svn_opt_revision_unspecified;
:
Here the some code from the PrintMesgStatusBox() function:
if(UseStatusBox())
{
int lbIndex = 0;
int length = vsprintf(statusMessage, format, args);
int printedLength = 0;
while((printedLength + STATUSBOX_LINE_LENGTH) < length)
{
char tempChar = statusMessage[printedLength + STATUSBOX_LINE_LENGTH];
statusMessage[printedLength + STATUSBOX_LINE_LENGTH] = '\0';
SendDlgItemMessage(hwndStatusBox, IDC_LIST1, LB_ADDSTRING, 0, (LPARAM)&statusMessage[printedLength]);
statusMessage[printedLength + STATUSBOX_LINE_LENGTH] = tempChar;
printedLength += STATUSBOX_LINE_LENGTH;
}
SendDlgItemMessage(hwndStatusBox, IDC_LIST1, LB_ADDSTRING, 0, (LPARAM)&statusMessage[printedLength]);
//AUTOSCROLL
lbIndex = SendDlgItemMessage(hwndStatusBox, IDC_LIST1, LB_GETCOUNT, 0, 0) - 1;
//Scroll to the newest item (put lbIndex to the top of the lb)
SendDlgItemMessage(hwndStatusBox, IDC_LIST1, LB_SETTOPINDEX, lbIndex, 0);
//redraw
UpdateWindow(hwndStatusBox);
:

Answer 1

The issue was that the message queue seemed no longer to be processed due to my code looping and communicating to the SVN server for a long time.
Since I have not control over the IDE implementation I had to do it in my dll.
I the loop I implemented a function which consumes and dispatches the messages for the dialogbox (resp. all messages).
The results were different if all or only the dialogbox message were consumed:
Consuming dialogbox messages only: The dialogbox would updated after every SVN communication which results in a rather choppy UI response to the user action. But the IDE menus stay in accessible which is wanted.
Consuming all messages: The UI response to the user is relatively smooth. But the IDE menus are accessible and the IDE can be close or other actions start. This is unwanted.
Hence I stay with only consuming the dialogbox messages.
Some code (function processing messages):
void ProcessMessages(HWND hWnd, BOOLEAN peekHwndMsgsOnly)
{
MSG msg;
HWND peekHwnd = NULL;
if(peekHwndMsgsOnly)
{
peekHwnd = hWnd;
}
while(PeekMessage(&msg, peekHwnd, 0, 0, PM_REMOVE))
{
if(!IsDialogMessage(hWnd, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
}
The loop originally blocking messages processing:
for(i=0; i<nFiles; i++)
{
/*
WaspLoggerLogPrintf(0, "%s - Processing: '%s' \n",
__FUNCTION__,
StripFilename(lpFileNames[i]));
*/
PrintMesgStatusBox("CheckFileStatus: for %s", StripFilename(lpFileNames[i]));
revison.kind = svn_opt_revision_unspecified;
youngest = SVN_INVALID_REVNUM;
internalfileName = svnApiSvnIface.fp_svn_dirent_internal_style(lpFileNames[i], pool);
if (updateFromRepo) { PrintMesgStatusBox(" Retrieving repo status..."); }
UpdateWindow(hwndParent);
ProcessMessages(hwndStatusBox, TRUE);
rtn = svnApiSvnIface.fp_svn_client_status4( &youngest, // svn_revnum_t *result_rev,
internalfileName, // const char *path,
&revison, // const svn_opt_revision_t *revision,
This might not be a very elegant solution but is serving the purpose.