UIAutomaition stuck when initializing while another thread loading a dll

Question

Background

I'm working on developing an app based on Chromium Project.

I found that the Widget::Show function is often stuck while another thread is executing LoadLibraryEx with a big dll file. And I want to speed up showing windows.

What I have tried

1. make a call of Widget::Show before loading the big dll, next time the Show function would not be stuck by Loader Lock (from LoadLibraryEx, I guess), which means the lock only affects the first time of calling the Show function.
2. I tried open a native window, using win32 api like CreateWindowEx, RegisterClass, ShowWindow, UpdateWindow. It also works when next time Widget::Show while loading dlls.
3. Loading a dll will get a lock, while other threads cannot load dlls or start a new thread.

Question

I guess UIAutomation set a hook and when some messages come, UIAutomation hooks it and do some initialization things like InitConnectionEvents, which will be locked by something.

I wonder is there any more elegant way to trigger UIAutomation "init" actions? Or how can I continue to debug this...

Stack

#0 Thread 23992 [CrBrowserMain]
 0  ntdll.dll!NtWaitForSingleObject + 0xc
    eip = 0x770c671c   esp = 0x0753d708   ebp = 0x0753d774   ebx = 0x00000000
    esi = 0x00000dbc   edi = 0x00000dc4   eax = 0x00000000   ecx = 0x00000000
    edx = 0x00000000   efl = 0x00000202
    Found by: given as instruction pointer in context
 1  KERNELBASE.dll!WaitForSingleObjectEx + 0x88
    eip = 0x760e19b8   esp = 0x0753d70c   ebp = 0x0753d774   ebx = 0x00000000
    Found by: call frame info
 2  KERNELBASE.dll!WaitForSingleObject + 0x12
    eip = 0x760e1922   esp = 0x0753d77c   ebp = 0x0753d788
    Found by: call frame info
 3  UIAutomationCore.DLL!OverlappedIOManager::AddChannel_AnyThread(ChannelInfo*, bool) + 0x67
    eip = 0x68bf1b18   esp = 0x0753d790   ebp = 0x0753d7c0
    Found by: call frame info
 4  UIAutomationCore.DLL!OverlappedIOManager::AddWorkQueueChannel(IWorkQueueChannel**) + 0x9a
    eip = 0x68beeb95   esp = 0x0753d7c8   ebp = 0x0753d7fc
    Found by: call frame info
 5  UIAutomationCore.DLL!ChannelBasedServerConnectionManager::SetupConnectionEvents(unsigned short const*, bool) + 0x30
    eip = 0x68bf14cc   esp = 0x0753d804   ebp = 0x0753de58
    Found by: call frame info
 6  UIAutomationCore.DLL!ChannelBasedServerConnectionManager::InitConnectionEvents(unsigned short const*, bool) + 0x45
    eip = 0x68d590c8   esp = 0x0753de60   ebp = 0x0753de70
    Found by: call frame info
 7  UIAutomationCore.DLL!HandleHookMessage(tagCWPSTRUCT*&) + 0x245
    eip = 0x68c48e5f   esp = 0x0753de78   ebp = 0x0753ee78
    Found by: call frame info
 8  UIAutomationCore.DLL!wil::slim_event_t<0>::wait(void) + 0x2e
    eip = 0x68d59970   esp = 0x0753de88   ebp = 0x0753eeb0
    Found by: stack scanning

the next call frames are like PeekMessage by Chromium run loop.