flowsizer: Use last width when width is 0
flowsizer: Use last width when width is 0

CollapsiblePane and flowsizer have issues when defining there sizes. To fix this issue
change flowsizer so that it will preserve globally (BAD.. ) the last width so that we can
use it instead of the default 0 size that is in our case always wrong.

robotframework/RIDE,fingeronthebutton/RIDE,fingeronthebutton/RIDE,caio2k/RIDE,HelioGuilherme66/RIDE,fingeronthebutton/RIDE,caio2k/RIDE,HelioGuilherme66/RIDE,robotframework/RIDE,HelioGuilherme66/RIDE,caio2k/RIDE,robotframework/RIDE,robotframework/RIDE,HelioGuilherme66/RIDE