Answers for Hu,
Someone once said about software development that " one human year is like ten years ".
Some of us here at CamSoft have been around for only a few years, so we are going to answer the questions as they pertain to the current version V15.3, which may or may not be related to the version you are using. Also there are 5 different levels plus a Lite and Plus versions as well.
(1) To directly answer your question. All you need is to use the ISTHERE command, which we don't know if you have or not. This way you can test to see IS THERE a \ backslash if so EXIT. You may even make an IF THEN test to see if a certain switch, button or toggle has Block Skip enabled or not to ignore this statement or make it automatic. We should also say that CNC Lite/Plus works the way you described already.
(2) In the current version you have several choices to select from to accomplish what you described. Three important methods include a command called INSPECT, Visual Mid-Program Restart using the graphics veiwport and a simpler point to a line of code and begin there in the MDI window. This first two are very powerful and addresses your desires. This last one you have and is nothing that special. We don't believe you have the first two methods and if you do, it has changed over the last couple of years, since you have had an update. We believe you would like both of these features very much.
(3) There is a lot to the Visual Program Re-Start feature. In short you can now zoom in and tumble the 3D graphics in the viewport to exactly choose the precise starting point. This may be mid-way on a line or half way on a circumference of an arc. if you make a mistake choosing there is also a pop-up information window that displays a few things such as the G code line your pointing to and mathematical intersection of the mouse and geometry item. There are several warnings, prompts and also the ability to manually insert extra code if need be. Keep picking until your satisfied then click on the green check ICON. There is a new brochure that you can download in either MS Word DOC file or PDF format on the left side menu of the home page called "Download Brochure" at www.cnccontrols.com The PDF file format is much more complete and more attractive.
(4) Things have changed, but first the key is after an edit should that change be permanent or temporary. If temporary a new job file is created called MDI.JOB file. Which if the change is good, then save it, under any name permanently. As you pointed out the reason for this that it is much less common to auto-save a temporary alteration of a file, and risk losing your edits on the "real" file. In the current version the save button does not exit the program, it hasn't for some time now. This allows you after an edit to simply press the save, run or exit button next. The .BAK file extension is a good idea, but you could now as easily rename the file while saving too then immediately run it.