This is under Vista SP1. There are errors in the log. I am going to attach log files. To make things more compact, I did try to reproduce the error with a fresh log, but even though the I repro'd the problem, the new log looks clean. Perhaps the errors are thrown when DF is starting up and Vista is starting up? I just did two reboots (one because of a sleep-of-death issue, and a second because a freak NT kernel error caused by Process Lasso). So you are going to see errors.log and displayfusion.log. The former has errors like below and clearly shows the first startup of v.105. The latter is clean though DF is misbehaving.

Jul 14, 2009 @ 12:08:09: TitleBarHelpers:GetTitleBarFormTop Failed to use GetCaptionButtonBounds.

You are correct, but they disappear onlyon the primary monitor. If I switch which monitor is primary and secondary (the 1 and the 2 shown in display settings), the new primary monitor cannot display the caption buttons when a window is maximized, but the original primary can. It's goofy, but true. See the two images for a demonstration of what it looks like. I've again attached a log since again there is errors.

BTW, just after hitting apply when switching which monitor is which, the button blinks a few times and then disappears almost as if it were trying to be on top and gets covered by the opaque maximized caption.

Sorry about the multiple attachments! I kept getting an error saying it failed to attach the attachments, so I did a back, changed the attachments and tried again. Apparently it did actually attach them, thus the dups! ops:

It happens on Windows Explorer and everything else, regardless of vendor. If it can be maximized, it shows the problem.

Here's the troubleshooting tab. I am running remote now, so I don't have a secondary monitor on, but I am experiencing the failure still. Note that I have 965 graphics on this tablet PC (see image). I can get other info, if you tell me where to look.

Note that I have FireFox maximized and DF knows that the caption button is not visible. Interesting...

--- Machine ------------
Operating System: Microsoft Windows NT 6.0.6001 Service Pack 1
Operating System Version: 6.0.6001.65536
Detected Version: WindowsVista / 2008
CPU: x86
Date/Time (UTC): 07/15/2009 18:33:45
Date/Time (Local): 07/15/2009 11:33:45
.NET Framework: 2.0.50727.3074
CurrentCulture: English (United States) (en-US ~ en)
CurrentUICulture: English (United States) (en-US ~ en)

--- Wallpaper ------------
Wallpaper Span: False
Monitor #1 Image: C:\Users\Robert\Pictures\Wall Paper\20090117_0767_Nasturium.JPG

--- DisplayFusion ------------
Name: DisplayFusion Pro v3.0.105 (Beta 5)
Build Date: Jul 14, 2009 00:34
Pro: True
Pro License: 101-POQR-3842-WHDQ (truncated)
Command Line: "C:\Program Files\DisplayFusion\DisplayFusion.exe"
Current Folder: C:\Program Files\DisplayFusion
Performance Mode: False
Mouse Hooks: True
Application Hooks: True
System Hooks Pause FullScreen: False

--- DisplayFusion x86 Hook DLL ------------
Path: C:\Program Files\DisplayFusion\DisplayFusionHookx86.dll
Name: DisplayFusion Hook
Prod Version: 1, 6, 0, 0
File Version: 1, 6, 0, 0
Size: 48,304 bytes

--- DisplayFusion x64 Hook DLL ------------
Path: C:\Program Files\DisplayFusion\DisplayFusionHookx64.dll
Name: DisplayFusion Hook
Prod Version: 1, 6, 0, 0
File Version: 1, 6, 0, 0
Size: 60,592 bytes

--- Monitor 1------------
Name: \\.\DISPLAY1
Primary: True
Bounds: {X=0,Y=0,Width=1024,Height=768}
WorkArea: {X=0,Y=0,Width=1024,Height=768}

--- Screens ------------
Count: 1
Point Min X: 0
Point Min Y: 0
Point Max X: 1024
Point Max Y: 768
Total Width: 1024
Total Height: 768
ActiveDesktop: False

--- Screen 1------------
ScreenID: 0
Device: \\.\DISPLAY1
Bounds: {X=0,Y=0,Width=1024,Height=768}
MoveH: 0
MoveV: 0

--- Managed Threads ------------
Count: 6
ID:3 ~ Name:TaskbarManager ~ Age:23:12:21.6903224 ~ Alive:True ~ BG:True ~ State:Background ~ Thread Name:TaskbarManager_999770b6-4b06-47e5-9ac5-2583d2923a3d
ID:4 ~ Name:TitleBarManager ~ Age:23:12:21.6873221 ~ Alive:True ~ BG:True ~ State:Background ~ Thread Name:TitleBarManager_d91241fb-3cf9-4bbf-b7d6-4f46d418e13a
ID:5 ~ Name:HookManager ~ Age:23:12:21.6823216 ~ Alive:True ~ BG:True ~ State:Background ~ Thread Name:HookManager_0224db55-c1b6-4939-86ec-36b7e6a3dc29
ID:7 ~ Name:HookFormProcess ~ Age:23:12:21.5363070 ~ Alive:True ~ BG:True ~ State:Background ~ Thread Name:HookFormProcess_576cc9ee-1199-4a5b-b5f0-07e980f72527
ID:34 ~ Name:Hook:WM_LBUTTONDOWN ~ Age:00:00:00.2850000 ~ Alive:False ~ BG ~ State:Stopped ~ Thread Name:Hook:WM_LBUTTONDOWN_a33d1ce2-ff54-4798-8b6c-ca0157974e3f
ID:17 ~ Name:TaskbarEnum ~ Age:00:00:00.2010000 ~ Alive:False ~ BG ~ State:Stopped ~ Thread Name:TaskbarEnum_be6d0d6a-878d-4193-95a5-60cc4c8dc4b0

--- Taskbars ------------
Enabled: True
Auto-hide: True
Visual Styles: True
Visual Styles Detected: True
DWM Composition Detected: True
Opacity: 100
Flash Blink: True
Window Options: AllShowAll
Button Width Max: 160
Sizing Bar Size: 0
Full Screen: 00000000 ~ {X=0,Y=0,Width=0,Height=0} ~ None
Count: 0

--- Deleted Items (0)------------
None

--- TitleBar Buttons ------------
Enabled: True
DisplayFusion Caption Button Size: {Width=32, Height=19}
System Caption Button Size: {Width=32, Height=19}
Count: 3
"Robert" (002a0268 ~ {X=69,Y=116,Width=800,Height=598} ~ Visible:False ~ Process64)
"Post reply - Mozilla Firefox" (00020958 ~ {X=-8,Y=-8,Width=1040,Height=784} ~ Visible:False ~ Process64)
"1. Xcultures - Sufi Mali (World Music - S K Y . F M - thanks for listening, visit us at www.sky.fm!" (00030730 ~ {X=187,Y=-30000,Width=550,Height=232} ~ Visible:True ~ Process64)