The Window configuration panel allows you to control aspects of the PuTTY window and its behaviour.
The Rows and Columns boxes let you set the PuTTY window to a precise size. Of course you can also drag the window to a new size while a session is running.
These options allow you to control what happens when the user tries to resize the PuTTY window.
When you resize the PuTTY window, one of three things can happen:
You can control which of these happens using the "Lock terminal size against resizing" and "Lock font size against resizing" options. If you lock both, the window will refuse to be resized at all. If you lock just the terminal size, the font size will change when you resize the window. If you lock just the font size, the terminal size will change when you resize the window.
Text that scrolls off the top of the PuTTY terminal window is kept for reference. The scrollbar on the right of the window lets you view the scrolled-off text. You can also page through the scrollback using the keyboard, by pressing Shift-PgUp and Shift-PgDn.
The "Lines of scrollback" box lets you configure how many lines of text PuTTY keeps. The "Display scrollbar" option allows you to hide the scrollbar (although you can still view the scrollback using Shift-PgUp and Shift-PgDn).
If you are viewing part of the scrollback when the server sends more text to PuTTY, the screen will revert to showing the current terminal contents. You can disable this behaviour by turning off "Reset scrollback on display activity". You can also make the screen revert when you press a key, by turning on "Reset scrollback on keypress".
If you press the Close button in a PuTTY window that contains a running session, PuTTY will put up a warning window asking if you really meant to close the window. A window whose session has already terminated can always be closed without a warning.
If you want to be able to close a window quickly, you can disable the "Warn before closing window" option.
By default, pressing ALT-F4 causes the window to close (or a warning box to appear; see section 3.6.4). If you disable the "Window closes on ALT-F4" option, then pressing ALT-F4 will simply send a key sequence to the server.
If this option is enabled, then pressing ALT-Space will bring up the PuTTY window's menu, like clicking on the top left corner. If it is disabled, then pressing ALT-Space will just send ESC SPACE to the server.
Some accessibility programs for Windows may need this option enabling to be able to control PuTTY's window successfully. For instance, Dragon NaturallySpeaking requires it both to open the system menu via voice, and to close, minimise, maximise and restore the window.
If this option is enabled, then pressing and releasing ALT will bring up the PuTTY window's menu, like clicking on the top left corner. If it is disabled, then pressing and releasing ALT will have no effect.
If this option is enabled, the PuTTY window will stay on top of all other windows.
If this option is enabled, then pressing Alt-Enter will cause the PuTTY window to become full-screen - that is, it will not only maximise itself, it will expand so that the title bar goes off the top of the screen, and place itself on top of the Windows taskbar, so that nothing is visible on the screen except PuTTY. Pressing Alt-Enter again will restore the previous window size.