Photo: Why does Brush tool morph into a small red X with a red line

[SDK4100]

I'm not sure what I may have activated. When I am trying to work with masks, I select a brush and when I click and drag the round brush turns into a small red x with a red line that trails along as I drag.  the leading edge is a very small circle.  When I release the mouse it goes back to a round brush.

Can anyone let me know what I did to engage this?  I can't figure out how to disengage this. I have searched the Affinity photo workbook and of course tried googling but i don't even know what to call it.  I am also not able to take a screen shot since it requires my mouse to be engaged for it to show and I don't know how to engage the mouse and engage capture

In case it's not obvious I am a beginner at affinity

Thanks to anyone who can clarify

Seth

PS: I am working on a Mac High Sierra

 

[GarryP]

Welcome to the forums @SDK4100
It sounds like you have switched the Stabiliser on in Rope Mode.
When the Stabiliser is switched on and in Rope Mode you need to drag the brush a certain distance to get it to do anything (this is expected as it needs this initial input to be able to calculate how to draw smoothly from the start).
See attached video.

[Pšenda]

With a weaker brush, it may be clearer.

[SDK4100]

Aha!  Thank you GarryP and Psenda!  that was it.  I don't know how i activated that.  I guess I need to pay more attention.

Many thanks. 

 

[GarryP]

You're welcome.