Dragging line of CTR measurement tool is difficult.

As a radiologist, I measure CTR using CTR measurement tool.

When measure CTR, I must adjust 4 lines of the tool to inner edge of ribs/edge of pleura every time.

To Drag these line, I should mouse over within around 1 or 2 pixels of the line.

In addition, mouse pointer is not changed even if I mouse over these line.

Expect behavior:

I can drag same as other tools(e.g. Distance tool).

- It can drag when mouse over within around 10 pixels of the line.

- When mouse over the line, mouse pointer is changed from arrow to finger.