Why is a registry file called a “hive”?

Useless trivia day. Why is a registry file called a “hive”? Because one of the original developers of Windows NT hated bees.  So the developer who was responsible for the registry snuck in as many bee references as he could.  A registry file is called a “hive”, and registry data are stored in “cells”, which…

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A subtlety in the keyboard code

I neglected to call it out explicitly in the text for Part 5:  Notice that I use cRepeat to determine how many lines/pages to scroll.  This allows us to scroll the correct amount even if we are falling behind on input processing and are missing some autorepeats.


Scrollbars bart 6 – The wheel

The mouse wheel is tricky because the mouse wheel UI guidelines indicate that you should scroll by a user-specified amount for each “click” of the mouse, where one click is WHEEL_DELTA mouse units (called a “detent”). There are two subtle points about the above requirement: First, that the amount of scrolling is a user setting…

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Limitations on DLL resources in Windows 95

Ancient history lesson. When Win9x loads a 32-bit DLL, it creates a shadow 16-bit DLL so 16-bit code (like USER) can access resources in it. The shadow DLL is effectively a resource-only 16-bit DLL, created by taking the 32-bit resources and converting them to 16-bit format. If the resources cannot be converted to 16-bit format,…

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Keyboard accessibility for scrollbars

Note that so far, the scrollbar is accessible only with the mouse. Our next step is to add keyboard access to the scrollbar. Fortunately, this is not all that difficult. We merely map some keystrokes to equivalent scrollbar actions. void OnKey(HWND hwnd, UINT vk, BOOL fDown, int cRepeat, UINT flags) { if (fDown) { switch…

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Changing the Windows boot logo

This is the answer I give to IT people when they ask if it’s okay to customize the Windows boot logo. DO NOT DO THIS ON A PRODUCTION MACHINE OR YOU WILL REGRET IT. If you hack the bitmap everything will seem fine until six months down the road when you decide to install the…

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Answer to previous exercise

If you look at the WM_VSCROLL message, you’ll see that the scroll position is a 16-bit value. So if the number of entries is more then 65535, you won’t be able to use the scroll thumb to get to the ones at the end. Try it: Change the value of g_cItems to 100000 and watch…


Scrollbars, part 4: Adding a proportional scrollbar

To obtain a proportional scrollbar, you need to tell Windows the minimum and maximum values covered by the scrollbar, the current scrollbar position, and the size of the scrollbar thumb (called the “page size”). One annoyance of the way scrollbars are set up is that the maximum value is attainable. This differs from the way…


Answer to yesterday’s exercise

iMin is the lowest-index element which intersects the paint rectangle, so a simple truncating division produces the desired index. The formula for iMax can be interpreted two ways. One is that it is the roundup of the first invisible line. Recall the rectangles are exclusive of the endpoint, so rcPaint.bottom is actually the first row…

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Why doesn’t the new Start menu use Intellimenus in the All Programs list?

Common request: I want to be able to turn on personalized menus (Intellimenus) when in XP Start Menu mode. Imagine if Intellimenus were enabled with the XP Start Menu. You use 5 apps; the rest are not used much. (Studies show that 5 is the typical number of unique applications users run on a regular…

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