Some window rule types, like Specific Settings and Exclusions, have a special set of criteria, called search condition, that allows you the precise identification of the target window. These criteria are based on the internal properties inherent to all windows and on any additional values assigned to specific windows by the Windows® operating system.
Actual Tools programs use the following three window properties for target window identification:
window class - internal window type identifier; i.e., its "system name". This is the most accurate method of target window identification although it's sometimes insufficient by itself, since many windows of the same class nevertheless differ significantly. A good example of such windows is an Explorer folder window: you can have several such folders open simultaneously in different windows but all of them will have the same window class value, so window class alone is insufficient to distinguish them from one other;
window program - the name of the main .EXE file for the application spawning a particular window or set of windows. Use this property to create a common setting for all the windows, associated with a single application, but note that "all" actually does mean ALL windows - including all program-related dialogs, queries, messages, alerts, etc.
You can combine criteria to make search condition restrictions more specific but be aware that - once specified - a target window so defined must conform to ALL such restrictions and not merely to any single one of them. In other words, this is an AND...AND situation and not an EITHER...OR. The more criteria you use the more precise the window specification (and the higher rule's preference rank). For example, if you activate the Window Class criterion for a rule and set its value to CabinetWClass then all folder windows will be affected by this rule. If, in addition to this, you activate the Window Caption criterion, select the substring match mode and set the value to music, then only folder windows displaying this partial substring in their caption - like My Music, Temporary Music Files, etc. - will be affected. If, on the other hand, you select the exact match mode and set the value to My Computer then only the "My Computer" folder window will be affected.
Note Even if you enabled all the three criteria and specified the exact match for the Window Caption (i.e. defined the strictest target window search condition) - it won't mean that you defined a target window search condition just for a single window; in any case, search condition describes a set of windows, because Windows® is a multi-tasking operating system. As a vivid explanation, let's take up the above-described example of search condition for the "My Computer" folder window: though specified criteria values unambiguously distinguish this window among other folder windows, you can nevertheless open as many "My Computer" folder windows as you wish, and all these windows will be affected by a single window rule. In other words, currently Actual Tools programs have no ability to distinguish instances of the same window.
While Actual Tools programs allow you supplying values for all these criteria manually they also provide two quick and easy magic tools - Window Finder and Window Selector - for the automatic retrieval and application of established values from windows you've already set up.