Sizer doesn’t work with all programs. Whilst I’ve tried my best to make it compatible with most popular programs, I can offer no guarantee that it will work.
Issues are typically seen because other applications don’t follow the standard way of doing things. Applications should let the operating system handle sizing and placement of the their windows. Unfortunately a growing class of applications ignore this: Firefox and iTunes are two of the common ones. There’s little I can do about this. If you experience a problem I suggest contacting the author of the application in question and ask them whether they handle WM_NCHITTEST messages correctly.
Such applications tend to ignore the "show contents when resizing" setting as well. They continue to show contents when resizing even when the setting is disabled.
In such cases System Tray Resizing will continue to work.
Sizer stores its configuration information in the registry under: HKEY_CURRENT_USER\Software\Sizer.
You can use regedit to export this key to a .reg file, copy it another machine and double click it to import it. (As an alternative to using regedit you can export the configuration to a file by using reg export "HKCU\Software\Sizer" sizer.reg at the command line.)
Sizer only asks an application to resize, whether the other application responds and does as it’s asked is up to the application. Most of the time it will behave correctly but Sizer can’t guarantee applications will do as they are asked.
There are technical challenges getting Sizer to work on 64 bit Windows. The issue is getting Sizer to work with work 64 bit applications and 32 bit bit applications. There is no official version supports 64 bit Windows, but version 3.4 aims to provide this functionality. See the Sizer 3.4 page for more information.
Sizer only moves or sizes a window such that it remains visible within the active monitor. Some users with multiple monitor find this behaviour frustrating but it’s by design. The motivation is to prevent a window disappearing by moving off the screen. An option may be added in a later version to offer more flexibility with multimonitor systems.
Sizer works by positioning a window relative to the active monitor. So on multiple monitor systems, this will be the current monitor not the overall desktop area. See the question above.
Sizer only asks an application to resize, how it is displayed is up to the application. Sometimes an application can’t cope with being a different size and it displays strange results. There’s little Sizer can do about this.
I know of no equivalent free program for Linux or Mac.
On the Mac, Mercury Mover offers the ability to move and resize windows using the keyboard. I've not used it myself so I can't say whether it's any good. It's also not freeware.
If you know any alternatives then please let me know.