For the Steam login window :
If I open it, and change workspace, the window is drawn (but not really present, the windows below get the clicks) on the workspace I moved to. It is drawn over the windows already there, and only "disappear", in part, when what is below is redrawn. Changing from there to another workspace without the Steam login window won't redraw it. Changing to the workspace containing the Steam login window and then again to a different workspace will make the Steam window redraw on that workspace.

For the client window, the same thing happen except no matter how many times I change workspaces (with or without going to the one where the window is) the Steam window is redrawn on them over the other windows. The Steam window is redrawn over the others every 1 or 2 seconds even without changing workspaces (unlike with the login window that is drawn once).

Other windows such as "About steam" or "system information" or "Product activation" work correctly even if they are opened over the client window. They don't get drawn on other workspaces.

The problem may be related to #3138 except I'm using xmonad as window manager and don't need to click any button to get that behavior.

It also may be related to #3099 except I don't try to "minimize" the window, because with my settings I'm not doing anything to "minimized" windows. I'm using xmonad with XMonad.Hooks.EwmhDesktops.

Also, it worked correctly in the past but I couldn't say which versions (of Steam and/or graphics drivers).

Processor Information:
    Vendor:  AuthenticAMD
    CPU Family:  0x15
    CPU Model:  0x2
    CPU Stepping:  0x0
    CPU Type:  0x0
    Speed:  4000 Mhz
    8 logical processors
    8 physical processors
    HyperThreading:  Unsupported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Supported
    SSE41:  Supported
    SSE42:  Supported

Network Information:
    Network Speed:  

Operating System Version:
    Linux 3.10 (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.12.9-2-ARCH
    X Server Vendor:  The X.Org Foundation
    X Server Release:  11500000
    X Window Manager:  xmonad
    Steam Runtime Version:  steam-runtime-release_2013-10-23

Video Card:
    Driver:  NVIDIA Corporation GeForce GTX 670/PCIe/SSE2

    Driver Version:  4.4.0 NVIDIA 331.38
    OpenGL Version: 4.4
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 60 Hz
    VendorID:  0x10de
    DeviceID:  0x1189
    Number of Monitors:  1
    Number of Logical Video Cards:  1
    Primary Display Resolution:  1920 x 1080
    Desktop Resolution: 1920 x 1080
    Primary Display Size: 20.08" x 11.42"  (23.07" diag)
                                            51.0cm x 29.0cm  (58.6cm diag)
    Primary Bus: PCI Express 16x
    Primary VRAM: 4096 MB
    Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
    Audio device: Realtek ALC892

Memory:
    RAM:  15954 Mb

Miscellaneous:
    UI Language:  English
    LANG:  en_US.UTF-8
    Microphone:  Not set
    Total Hard Disk Space Available:  275947 Mb
    Largest Free Hard Disk Block:  96066 Mb