Symbols used in 2D view

[Marmadoc]

In 2D view I have 2 markers (ikon or symbols - i do not know). One is black square - I understand it represents tool position, but what is red square - is jumping when I click on 2D are - what it represents? Maybe it is trivial question - but can't find answer.

[svenhb]

The red marker shows the coordinate of the actual marked line:

• click into a specific G-Code line, the marker shows the coordinate in the 2-D view
• do alt-click in 2-D view to set marker to the closest code-coordinate, the coresponding code-line will be shown
• during streaming, the red marker shows the last sent coordinate, towards the grbl-controller

[Marmadoc]

Thank you so much. Now it is easy.