1. A computer-implemented method for controlling a size and content of a hierarchical visualization by a software component executing on a computer, the method performed by the software component, comprising: displaying a multi-level hierarchical visualization of nodes, including a node representing a collapsed sub-hierarchy that is displayed using a collapsed sub-hierarchy symbol that is not applied to regular nodes; responsive to a user invoking a contextual search by performing a user gesture on the collapsed sub-hierarchy symbol, displaying a contextual search dialog box located adjacent to the collapsed hierarchy symbol that displays a text entry field for the user to enter search criteria that is contextual only to the collapsed sub-hierarchy, wherein the contextual search dialog further displays a total number of hidden units comprising the collapsed sub-hierarchy; responsive to the user entering the search criteria, displaying search results comprising any nodes from the collapsed sub-hierarchy matching the search criteria, wherein the search results are displayed directly in the contextual search dialog box to control the size of the hierarchical visualization; receiving a user selection of which ones of the matching nodes from the collapsed sub-hierarchy to show in the hierarchical visualization; and displaying a partial rendering of the collapsed sub-hierarchy that shows the selected matching nodes while keeping remaining non-matching nodes hidden, wherein other nodes linked to the matching nodes representing a collapsed sub-hierarchy are displayed using the collapsed sub-hierarchy symbol that is not applied to regular nodes.