I have a tk text widget that displays 4 lines of text. A button adds a tag (mytag) to the whole line containing the insertion cursor.
Below is a dump of the text. The tag has been applied to the third line.
As you can see there is an anchor mark in the middle of it (at position 16, which is where the mouse was clicked).
What is the best way to access all the text within the tag? Is it possible to move/reset the anchor mark?

key: mark,   value: current, index: 1.0
key: text,   value: Twas brillig, and the slithy toves, index: 1.0
key: text,   value: Did gyre and gimble in the wabe:, index: 2.0
key: tagon,  value: mytag, index: 3.0
key: text,   value: All mimsy were t, index: 3.0
key: mark,   value: anchor, index: 3.16
key: text,   value: he borogoves,, index: 3.16
key: tagoff, value: mytag, index: 3.29
key: text,   value: , index: 3.29
key: mark,   value: insert, index: 4.0
key: text,   value: And the mome raths outgrabe., index: 4.0
key: text,   value: , index: 5.0
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Update:
$t->markUnset('anchor');
Seems to do the trick!