Text not readable with fill styling when htmlLabels false

[stanhu]

Describe the bug

When htmlLabels is set to false, the text in a flow diagram doesn't show when styling the background.

To Reproduce

Initiate Mermaid with htmlLabels: false and use this diagram:

graph LR

SavePropertyController --> SavePropertyCommand
SavePropertyCommand --> SavePropertyCommandHandler
SavePropertyCommandHandler --> EventElastica[elastica.postupdate]
SavePropertyCommandHandler --> EventProperty[property.postdisable]

SavePropertyController --> Exceptions
Exceptions --> ExceptionList(SecurityException<br/>EmptyRequestBodyException<br/>Throwable)

classDef Ui fill:#FFFFFF
classDef object fill:#1E98EC
classDef event fill:#ECB11E

class EventElastica,EventProperty event
class SavePropertyCommand,SavePropertyCommandHandler object
class SavePropertyController Ui

Expected behavior

When htmlLabels: true, this is how it looks:

Screenshots

However, this is what actually happens:

The htmlLabels: true case produces this:

While htmlLabels: false case produces this:

Desktop (please complete the following information):

MacOS Mojave 10.14.12
Chrome 75.0.3770.142

[stanhu]

It looks like the tspan element needs a fill argument:

diff --git a/src/diagrams/flowchart/flowRenderer.js b/src/diagrams/flowchart/flowRenderer.js
index 3fb9a31..1d7eb46 100644
--- a/src/diagrams/flowchart/flowRenderer.js
+++ b/src/diagrams/flowchart/flowRenderer.js
@@ -79,6 +79,7 @@ export const addVertices = function (vert, g, svgId) {
         tspan.setAttribute('dy', '1em')
         tspan.setAttribute('x', '1')
         tspan.textContent = rows[j]
+        tspan.setAttribute('fill', 'black')
         svgLabel.appendChild(tspan)
       }
       vertexNode = svgLabel