+\r
+<p><strong>The PCA Viewer</strong></p>\r
+<p>This is an interactive display of the sequences positioned within\r
+ the similarity space. The colour of each sequence point is the same\r
+ as the sequence group colours, white if no colour has been\r
+ defined for the sequence, and green if the sequence is part of a\r
+ the currently selected group.\r
+</p>\r
+ <p>The 3d view can be rotated by dragging the mouse with the\r
+ <strong>left mouse button</strong> pressed. The view can also be\r
+ zoomed in and out with the up and down <strong>arrow\r
+ keys</strong>.</p>\r
+<p>A tool tip gives the sequence ID corresponding to a point in the\r
+ space, and clicking a point toggles the selection of the\r
+ corresponding sequence in the alignment window. Rectangular region\r
+ based selection is also possible, by holding the 'S' key whilst\r
+ left-clicking and dragging the mouse over the display.\r
+</p>\r
+<p>Initially, the display shows the first three components of the\r
+ similarity space, but any eigenvector can be used by changing the selected\r
+ dimension for the x, y, or z axis through each ones menu located\r
+ below the 3d display.\r
+</p>\r
+\r