There are some Unicode characters whose width is not well-defined. In most contexts, such characters should be treated as single-width for the purposes of wrapping and so on; however, in some CJK contexts, they are better treated as double-width for historical reasons, and some server-side applications may expect them to be displayed as such. Setting this option will cause PuTTY to take the double-width interpretation. If you use legacy CJK applications, and you find your lines are wrapping in the wrong places, or you are having other display problems, you might want to play with this setting.
4.10.3 ‘Caps Lock acts as Cyrillic switch’ This feature allows you to switch between a US/UK keyboard layout and a Cyrillic keyboard layout by using the Caps Lock key, if you need to type (for example) Russian and English side by side in the same document. Currently this feature is not expected to work properly if your native keyboard layout is not US or UK.
4.10.4 Controlling display of line-drawing characters VT100-series terminals allow the server to send control sequences that shift temporarily into a separate character set for drawing simple lines and boxes. However, there are a variety of ways in which PuTTY can attempt to find appropriate characters, and the right one to use depends on the locally configured font. In general you should probably try lots of options until you find one that your particular font supports. •‘Use Unicode line drawing code points’ tries to use the box characters that are present in Unicode. For good Unicode-supporting fonts this is probably the most reliable and functional option. •‘Poor man's line drawing’ assumes that the font cannot generate the line and box characters at all, so it will use the +, - and | characters to draw approximations to boxes. You should use this option if none of the other options works.
•‘Font has XWindows encoding’ is for use with fonts that have a special encoding, where the lowest 32 character positions (below the ASCII printable range) contain the line-drawing characters. This is unlikely to be the case with any standard Windows font; it will probably only apply to custom-built fonts or fonts that have been automatically converted from the X Window System.
•‘Use font in both ANSI and OEM modes’ tries to use the same font in two different character sets, to obtain a wider range of characters. This doesn't always work; some fonts claim to be a different size depending on which character set you try to use.
•‘Use font in OEM mode only’ is more reliable than that, but can miss out other characters from the main character set.
4.10.5 Controlling copy and paste of line drawing characters By default, when you copy and paste a piece of the PuTTY screen that contains VT100 line and box drawing characters, PuTTY will paste them in the form they appear on the screen: either Unicode line drawing code points, or the ‘poor man's’ line-drawing characters +, - and |. The checkbox ‘Copy and paste VT100 line drawing chars as lqqqk’ disables this feature, so line-drawing characters will be pasted as the ASCII characters that were printed to produce them. This will typically mean they come out mostly as q and x, with a scattering of jklmntuvw at the corners. This might be useful if you were trying to recreate the same box layout in another program, for example. Note that this option only applies to line-drawing characters which were printed by using the VT100 mechanism. Line-drawing characters that were received as Unicode code points will paste as Unicode always.
The Selection panel allows you to control the way copy and paste work in the PuTTY window.