I upgraded the plugin, and now SketchUp automatically show the dimensions, without click menu item and hotkey, and this feature can be disabled if it interferes.

Download link:
Dimensions Tool

Menu:
Tools > Dimensions Tool > Get Dimensions - old functional
Tools > Dimensions Tool > Auto Display Dimensions - checked menu item, which switch auto get dimensions functionality after select object.

P.S. Let me know if you need to modify the algorithm and move plugin to another menu for the convenience.

Hi, all.

This, I modified the plugin Get Dimensions. If you have any questions I can answer.

Thank dedmin, that upload changed plugin. I looked at the comments in the forum and would immediately respond.

1. I did not change the algorithm for determining the length, width and height, and left it in its original form, only changed the location of information display.

2. Call plugin from the menu is not convenient, since after a mouse movement information is lost. But it is very convenient to assign a hot key, such as (W), and using the command Select, selected element, press W, and the information appears at the bottom, select the next element, and then press W again appear at the bottom of the data about the object. As for me it is very convenient. In this Select command is not disabled, which is also very convenient.