Description of problem:
Process Instance Details panel opens when a row is selected in Process Instances table. It has Process Variables tab where process instance variables can be viewed and edited. However variable values are trimmed to 255 characters. That means when a variable value is longer than 255 chars, the user is presented with an incomplete information. If the variable was read-only it would be acceptable but the user is allowed to edit & save the incomplete information which inevitably results in data loss.

Version-Release number of selected component (if applicable):
6.2.0.CR1

How reproducible:
-

Steps to Reproduce:
1. Create a managed multi-project repository (in Administration).
2. In Project authoring, Repository structure, add new module.
3. Start promotion from master to dev or release branch.
4. Go to Process Management -> Process Instances, select PromoteAssets instance.
5. Select Process Variables tab, edit "Commits" variable.
6. Select the variable value, paste it into a text editor.

Actual results:
Adding a new module will create many files, so some of the PromoteAssets variables will exceed 255 characters. When editing Commits variable it's value is:

[
  CommitInfo{
    commitId='6c9520d494114c1ab54b31c7afec0c06b89d94ff',
    message='New project [bug]',
    author='assman',
    commitDate=Wed Nov 18 12:54:10 CET 2015,
    files=[bug/.global, bug/global/.gitignore, bug/global/backboneformsinclude.fw, bug/global/backbonejsinc

which is only 255 chars and obviously incomplete.

Expected results:
When editing process instance variable, the complete value should be shown, or the variable should be read-only if complete value cannot be presented.

Additional info: