Dima,
I don't think there is any feature that is quite like you describe. However, I can suggest several ways you might be able to go about this without too much work.
EA allows you to assign some properties to an element that go beyond what UML requires. You can assign keywords, but these are kind of free-form, and not quite automatic. However...
You can assign a Status [capitalized to match the element Properties dialogs] to any element. EA generally defaults the value of this property to "Proposed." This default value might work just fine for you. There are a standard set of Status values, and you can add your own via the Settings | General Types dialog (which defaults to the Status tab). Note that there is also a Constraint Status tab, allowing you to handle constraints separately.
If you set up your own Status values, they are stored as Reference Data, and may be exported and loaded into other projects.
[Note that the default is (probably) set in the EABase project that is installed with EA. You could edit this project to set up a different default, which could be one of your custom values.]
The nice thing about setting a Status value, is that EA can use these values to highlight elements. You will generally see this in regards to Requirement elements and such, but EA will actually allow you to highlight just about anything.
You enable this in a three step process. [You can do this in fewer steps, but it sometimes helps to explain it this way the first time.] First open the Tools | Options | Objects dialog, and check the box labeled Show status colors on diagrams. Now go (back) to the Settings | General Types dialog (and the Status or Constraint Status tab as appropriate). For each Status value you intend to use, click the Applies to button, and check the element types you want to highlight. Each Status value can be set independently. In many cases, such as Requirement elements, you're all done.
Now for the third (and most mysterious) step. For many elements (such as Class elements) the status color will only show if EA is drawing element shadows. So, you need to turn this setting on. You'll find the setting back on the Tools | Options | Objects dialog; check the Shadows On box.
If the Status method doesn't work for you, perhaps you can assign a stereotype of «draft» or something, when you first create an element. You can accelerate this process by adding the stereotype to the Settings | UML | Stereotypes dialog. This way it will appear on the Stereotype drop-down of the element's properties dialog. You can type the first letter or two and press the down arrow key; EA will do the rest.
If you use a stereotype, make sure you don't have EA set to ignore stereotypes when rendering a diagram. [Or, make sure you do have EA ignore it if you want to display diagrams without it for some reason.] The setting you need is on the Elements tab of the diagram Properties dialog. Check or clear the Show Element Stereotypes box. There is also a setting for features (attributes, operations, and such). It is names Show Stereotypes, and is found on the Features tab.
There's a related setting on the Tools | Options | General dialog. If you check the Show Stereotypes box in the Project Browser settings, you will see your stereotype (and any others) in the Project Browser tree. You should set this as appropriate for your needs.
Finally, you can bookmark the element. EA uses bookmarks to draw your attention to an element for quick reference, which is what you want to do here. To set a bookmark, highlight an element and press Shift-Space. You'll see a little red triangle at the top of the element. To remove a bookmark, do the same thing again: select the element and press Shift-Space.
[BTW, bookmarks - or more accurately the "little red triangles" - are one of the least understood features of EA. What the "triangles" mean, where they come from, and most importantly how to get rid of them, are among the most common user questions.]
Note that any or all of the above can be used in combination.
HTH, David