diff --git a/src/qt/qt_glsl_parser.cpp b/src/qt/qt_glsl_parser.cpp
index 9a0a0fc03..e5c7b77f2 100644
--- a/src/qt/qt_glsl_parser.cpp
+++ b/src/qt/qt_glsl_parser.cpp
@@ -17,6 +17,7 @@ extern "C"
 #include <86box/config.h>
 #include <86box/qt-glslp-parser.h>
 #include <86box/path.h>
+#include <86box/plat.h>
 
 extern void startblit();
 extern void endblit();
@@ -81,14 +82,38 @@ static int endswith(const char *str, const char *ext) {
         return 0;
 }
 
+static int
+glsl_detect_bom(const char *fn)
+{
+    FILE         *fp;
+    unsigned char bom[4] = { 0, 0, 0, 0 };
+
+    fp = plat_fopen(fn, "rb");
+    if (fp == NULL)
+        return 0;
+    (void) !fread(bom, 1, 3, fp);
+    if (bom[0] == 0xEF && bom[1] == 0xBB && bom[2] == 0xBF) {
+        fclose(fp);
+        return 1;
+    }
+    fclose(fp);
+    return 0;
+}
+
 static char *load_file(const char *fn) {
-        FILE *f = fopen(fn, "rb");
+        int bom = glsl_detect_bom(fn);
+        FILE *f = plat_fopen(fn, "rb");
         if (!f)
                 return 0;
         fseek(f, 0, SEEK_END);
         long fsize = ftell(f);
         fseek(f, 0, SEEK_SET);
 
+        if (bom) {
+                fsize -= 3;
+                fseek(f, 3, SEEK_SET);
+        }
+
         char *data = (char*)malloc(fsize + 1);
 
         fread(data, fsize, 1, f);
@@ -131,12 +156,15 @@ static int get_parameters(glslp_t *glsl) {
         int i;
         struct parameter p;
         for (i = 0; i < glsl->num_shaders; ++i) {
+                char line[1024];
                 struct shader *shader = &glsl->shaders[i];
-                FILE *f = fopen(shader->shader_fn, "rb");
+                int bom = glsl_detect_bom(shader->shader_fn);
+                FILE *f = plat_fopen(shader->shader_fn, "rb");
                 if (!f)
                         return 0;
-
-                char line[1024];
+                if (bom) {
+                        fseek(f, 3, SEEK_SET);
+                }
                 while (fgets(line, sizeof(line) - 1, f) && glsl->num_parameters < MAX_PARAMETERS) {
                         int num = sscanf(line, "#pragma parameter %63s \"%63[^\"]\" %f %f %f %f", p.id, p.description,
                                          &p.default_value, &p.min, &p.max, &p.step);
diff --git a/src/qt/qt_openglshadermanagerdialog.cpp b/src/qt/qt_openglshadermanagerdialog.cpp
index 7f8a19414..72f58f9cb 100644
--- a/src/qt/qt_openglshadermanagerdialog.cpp
+++ b/src/qt/qt_openglshadermanagerdialog.cpp
@@ -63,6 +63,7 @@ OpenGLShaderManagerDialog::OpenGLShaderManagerDialog(QWidget *parent)
         } else {
             ui->buttonConfigure->setEnabled(false);
         }
+        ui->buttonAdd->setDisabled(ui->shaderListWidget->count() >= MAX_USER_SHADERS);
     } else {
         ui->buttonRemove->setDisabled(true);
         ui->buttonMoveUp->setDisabled(true);
@@ -177,6 +178,7 @@ void OpenGLShaderManagerDialog::on_buttonAdd_clicked()
             item->setData(Qt::UserRole + 2, (qulonglong)(uintptr_t)shaderfile);
             if (ui->shaderListWidget->count()) {
                 ui->shaderListWidget->setCurrentRow(ui->shaderListWidget->count() - 1);
+                ui->buttonAdd->setDisabled(ui->shaderListWidget->count() >= MAX_USER_SHADERS);
             }
         } else {
             QMessageBox::critical(this, tr("GLSL error"), tr("Could not load filename %1").arg(res));
@@ -197,6 +199,7 @@ void OpenGLShaderManagerDialog::on_buttonRemove_clicked()
 
         on_shaderListWidget_currentRowChanged(ui->shaderListWidget->currentRow());
     }
+    ui->buttonAdd->setDisabled(ui->shaderListWidget->count() >= MAX_USER_SHADERS);
 }
 
 void OpenGLShaderManagerDialog::on_OpenGLShaderManagerDialog_accepted()