BPEL Editor: Editor Assistance & Visual Feedback on Drag'n'Drop
$Revision: 1.1.1.1 $
$Date: 2009/10/29 16:50:07 $
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Use Case: User wants to add something to the diagram, but it is not
allowed
User may try to Drag'n'Drop various artefacts on the canvas; however, this may not be possible due to current settings of the process or the object.
Scenario
The scenario is depicted on the following storyboard. Click on the picture to get to the next step.

Step 1 - Initial State: The sequences are shown.

Step 2 - User enables the sequence filter. Sequences are hidden (this might be the default settings though).

Step 3 - User tries to Drag'n'Drop a sequence from the Palette on the diagram.

Step 4 - User is given a negative visual feedback and an explanation.

Step 5 - As the user moves the mouse pointer, the message follows it.
Design Details
Item |
Mockup |
Description |
Font |
- |
Face: standard platform, Style:
bold, Color: red - RGB (255, 0, 0) |
Background |
- |
A filled rectangle with RGB(255,
255, 220), with 2 px inset around icon and text (if the text is smaller
then it will be). |
Mouse pointer position |
- |
In the center of the rectangle
horizontally, just under the rectangle vertically. |
Icon |
![]() |
4 px inset between icon and
message text |
Open questions
- Should ghost image be shown? I think no as the sequence cannot be
dropped.
- Should the placeholders be shown? I think no as there is no valid drop point.
- Wording of the message. Proposals:
There is an issues with the wording of these messages (the conflicting meaning of filter, show and false/disabled).
"Cannot add sequence when the filter Show Sequence is disabled."
"Cannot add new sequnce to diagram while Filter Show Sequnce set to false"
However, as we are going to replace the filter pull down with toolbar toggle buttons (toggled will mean 'show' and there will be tooltip "Show Sequences"), we could have messages like this:
"Cannot add sequence when sequences are not shown."
Alternative Design
Instead of on-place error message, editor assistant (top bar) could be used. However, we have seen this approach as inefficient, during the usability study. Users often missed the message in the editor assistant, but they never missed the message near the mouse pointer location or on the drop points.
