Release version 2.4.0

• This version introduces a new type of factor: 'Portals'. A portal factor is a special type of factor that links to another map. When you click on a portal factor, the map it links to will open in a new browser tab. This useful when, for example, you have several related maps and want to move easily between them. It is also useful if you have a high level or abstract map. Portal factors on this map can link to more detailed maps that expand on the factors in the high level one. See Linking one map to another for further details.
• When opening a map from a file, you can now choose whether the map should replace the existing map, or be merged with it. See Merging Maps.
• The colour picker, used to choose the colour of factors, links, background shapes and the map background, has been enhanced to control the transparency of the colour. One use of this is that if you make the map background transparent and then obtain a high definition image of the map, that image will also have a transparent background, which can be helpful when incorporating the image into a web page.
• When creating a 'read-only' copy of a map, you can choose whether to include a 'Copy map' button in the top bar. If you do, viewers cannot change the read only map, but they can create a fully editable copy of the map in a new room, displayed in a new browser tab.
• The User Manual has ben formatted and extended and you can now search it.
• And bug fixes and security updates.