Perspective button in view stays in pressed state

I have created an application to track our internal IP address usage. It features a button in a view (render: veiw, viewPath: viewPingButton) which opens a popup which runs the ping test.

Ping button select

The problem is that after the popup has been closed the button can’t be pressed a second time unless the user clicks elsewhere on the table to de-select the cell’s rendered view. The column is set to editable: false. It’s as though the button is being held down and needs to have the focus removed from it.

Any ideas?

For anyone interested, the popup looks like this:

Ping popup

The red label is lblPingStatus and has a custom prop pingResult which is used to control the caption and color.

and the code like this:

def runAction(self):
	self.getChild("lblPingStatus").custom.pingResult = -1	# Suppress any previous results.
	self.getChild("lblHelper").meta.visible = False
	import datetime
	import os			# Required for ping operation
	import re			# Required to strip leading zeros from IP address octets.
	timeout = 1500 		# ping timeout (ms).

	shortIp = re.sub('(^|\.)0+(?=[^.])', r'\1', self.view.params.value.IpAddress)			# Strip the leading zeros from each octet or Windows ping won't find it!	
	# For Windows: -n 1 = ping once. -w 200 = timeout value.
	# r = os.system('ping -n 1 -w ' + str(timeout) + ' ' + shortIp) == 0					# Python method superceded.
	# os.system('ping -c 1 {}'.format(myip))      											See
	r = os.system('ping -n 1 -w ' + str(timeout) + ' {}'.format(shortIp)) == 0
	#  1 = Good.
	#  0 = Nothing.	
	self.getChild("lblPingStatus").custom.pingResult = r   
	if r == 0:
		self.getChild("lblHelper").props.text = 'No response in ' + str(timeout) + ' ms'
		self.getChild("lblHelper").meta.visible = True,